diff --git a/CHANGELOG.md b/CHANGELOG.md
index b8bb68328..973dbdcac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 
 ## [Unreleased]
 
+### Added
+
+- `cz`: Added the Czech Republic DPH (VAT) regime with 21% standard, 12% reduced (2024 consolidation), and historical rates back to 2004. DIČ validation with three format types and IČO business registration identity.
+
 ## [v0.400.0] - 2026-14-15
 
 Final release of the rules based changes.
diff --git a/data/regimes/cz.json b/data/regimes/cz.json
new file mode 100644
index 000000000..53cc6ae49
--- /dev/null
+++ b/data/regimes/cz.json
@@ -0,0 +1,186 @@
+{
+  "$schema": "https://gobl.org/draft-0/tax/regime-def",
+  "name": {
+    "cs": "Česká republika",
+    "en": "Czech Republic"
+  },
+  "description": {
+    "en": "The Czech Republic's tax system is administered by the Financial\nAdministration of the Czech Republic (Finanční správa ČR). As an EU member\nstate, the Czech Republic follows the EU VAT Directive.\n\nVAT (DPH — Daň z přidané hodnoty) applies at a standard rate of 21% and a\nsingle reduced rate of 12% (since January 2024, when the previous first\nreduced rate of 15% and second reduced rate of 10% were merged). Certain\nsupplies are zero-rated (e.g. exports) or exempt (e.g. healthcare,\neducation, financial services).\n\nBusinesses are identified by their DIČ (Daňové identifikační číslo), which\nconsists of the prefix CZ followed by 8 to 10 digits. For legal entities\nthe DIČ is 8 digits with a modulo-11 checksum; for individuals it is\nderived from the birth number (Rodné číslo) and is 9 or 10 digits."
+  },
+  "time_zone": "Europe/Prague",
+  "country": "CZ",
+  "currency": "CZK",
+  "tax_scheme": "VAT",
+  "identities": [
+    {
+      "key": "cz-ico",
+      "name": {
+        "cs": "Identifikační číslo osoby",
+        "en": "Business Registration Number"
+      }
+    }
+  ],
+  "corrections": [
+    {
+      "schema": "bill/invoice",
+      "types": [
+        "credit-note",
+        "debit-note"
+      ]
+    }
+  ],
+  "categories": [
+    {
+      "code": "VAT",
+      "name": {
+        "cs": "DPH",
+        "en": "VAT"
+      },
+      "title": {
+        "cs": "Daň z přidané hodnoty",
+        "en": "Value Added Tax"
+      },
+      "keys": [
+        {
+          "key": "standard",
+          "name": {
+            "en": "Standard"
+          }
+        },
+        {
+          "key": "zero",
+          "name": {
+            "en": "Zero"
+          }
+        },
+        {
+          "key": "reverse-charge",
+          "name": {
+            "en": "Reverse charge"
+          },
+          "no_percent": true
+        },
+        {
+          "key": "exempt",
+          "name": {
+            "en": "Exempt"
+          },
+          "no_percent": true
+        },
+        {
+          "key": "export",
+          "name": {
+            "en": "Export"
+          },
+          "no_percent": true
+        },
+        {
+          "key": "intra-community",
+          "name": {
+            "en": "Intra-community"
+          },
+          "no_percent": true
+        },
+        {
+          "key": "outside-scope",
+          "name": {
+            "en": "Outside scope"
+          },
+          "no_percent": true
+        }
+      ],
+      "rates": [
+        {
+          "rate": "general",
+          "keys": [
+            "standard"
+          ],
+          "name": {
+            "cs": "Základní sazba",
+            "en": "Standard Rate"
+          },
+          "values": [
+            {
+              "since": "2013-01-01",
+              "percent": "21.0%"
+            },
+            {
+              "since": "2010-01-01",
+              "percent": "20.0%"
+            },
+            {
+              "since": "2004-05-01",
+              "percent": "19.0%"
+            }
+          ]
+        },
+        {
+          "rate": "reduced",
+          "keys": [
+            "standard"
+          ],
+          "name": {
+            "cs": "Snížená sazba",
+            "en": "Reduced Rate"
+          },
+          "values": [
+            {
+              "since": "2024-01-01",
+              "percent": "12.0%"
+            },
+            {
+              "since": "2013-01-01",
+              "percent": "15.0%"
+            },
+            {
+              "since": "2012-01-01",
+              "percent": "14.0%"
+            },
+            {
+              "since": "2010-01-01",
+              "percent": "10.0%"
+            },
+            {
+              "since": "2008-01-01",
+              "percent": "9.0%"
+            },
+            {
+              "since": "2004-05-01",
+              "percent": "5.0%"
+            }
+          ]
+        },
+        {
+          "rate": "super-reduced",
+          "keys": [
+            "standard"
+          ],
+          "name": {
+            "cs": "Druhá snížená sazba",
+            "en": "Second Reduced Rate"
+          },
+          "values": [
+            {
+              "since": "2015-01-01",
+              "percent": "10.0%"
+            }
+          ]
+        }
+      ],
+      "sources": [
+        {
+          "title": {
+            "en": "Czech Republic - General rules and VAT rates"
+          },
+          "url": "https://portal.gov.cz/en/informace/general-rules-and-vat-rates-INF-205"
+        },
+        {
+          "title": {
+            "en": "Registering for VAT in the Czech Republic"
+          },
+          "url": "https://portal.gov.cz/en/informace/registering-for-vat-INF-204"
+        }
+      ]
+    }
+  ]
+}
\ No newline at end of file
diff --git a/data/schemas/tax/regime-code.json b/data/schemas/tax/regime-code.json
index a8fdd8b8d..c5852494d 100644
--- a/data/schemas/tax/regime-code.json
+++ b/data/schemas/tax/regime-code.json
@@ -37,6 +37,10 @@
           "const": "CO",
           "title": "Colombia"
         },
+        {
+          "const": "CZ",
+          "title": "Czech Republic"
+        },
         {
           "const": "DE",
           "title": "Germany"
diff --git a/examples/cz/invoice-cz-cz.yaml b/examples/cz/invoice-cz-cz.yaml
new file mode 100644
index 000000000..c671b2a72
--- /dev/null
+++ b/examples/cz/invoice-cz-cz.yaml
@@ -0,0 +1,45 @@
+$schema: https://gobl.org/draft-0/bill/invoice
+$regime: CZ
+uuid: 8c042838-29e4-4f96-b202-15f0e1c3e224
+currency: CZK
+series: "2025"
+code: "001"
+issue_date: "2025-06-15"
+
+supplier:
+  name: "Příklad s.r.o."
+  tax_id:
+    country: CZ
+    code: "00177041"
+  addresses:
+    - street: "Vodičkova 791/41"
+      locality: "Praha"
+      code: "110 00"
+      country: CZ
+
+customer:
+  name: "Zákazník a.s."
+  tax_id:
+    country: CZ
+    code: "45274649"
+  addresses:
+    - street: "Duhová 1444/2"
+      locality: "Praha"
+      code: "140 53"
+      country: CZ
+
+lines:
+  - quantity: "10"
+    item:
+      name: "Softwarové poradenství"
+      price: "1500.00"
+    taxes:
+      - cat: VAT
+        rate: standard
+  - quantity: "5"
+    item:
+      name: "Knihy"
+      price: "250.00"
+    taxes:
+      - cat: VAT
+        rate: reduced
diff --git a/examples/cz/out/invoice-cz-cz.json b/examples/cz/out/invoice-cz-cz.json
new file mode 100644
index 000000000..da9ba8c6b
--- /dev/null
+++ b/examples/cz/out/invoice-cz-cz.json
@@ -0,0 +1,118 @@
+{
+	"$schema": "https://gobl.org/draft-0/envelope",
+	"head": {
+		"uuid": "8a51fd30-2a27-11ee-be56-0242ac120002",
+		"dig": {
+			"alg": "sha256",
+			"val": "67b484fdbb62747f84f1dd1d252428939a2cf0b401aa497a07180a42221e9436"
+		}
+	},
+	"doc": {
+		"$schema": "https://gobl.org/draft-0/bill/invoice",
+		"$regime": "CZ",
+		"uuid": "8c042838-29e4-4f96-b202-15f0e1c3e224",
+		"type": "standard",
+		"series": "2025",
+		"code": "001",
+		"issue_date": "2025-06-15",
+		"currency": "CZK",
+		"supplier": {
+			"name": "Příklad s.r.o.",
+			"tax_id": {
+				"country": "CZ",
+				"code": "00177041"
+			},
+			"addresses": [
+				{
+					"street": "Vodičkova 791/41",
+					"locality": "Praha",
+					"code": "110 00",
+					"country": "CZ"
+				}
+			]
+		},
+		"customer": {
+			"name": "Zákazník a.s.",
+			"tax_id": {
+				"country": "CZ",
+				"code": "45274649"
+			},
+			"addresses": [
+				{
+					"street": "Duhová 1444/2",
+					"locality": "Praha",
+					"code": "140 53",
+					"country": "CZ"
+				}
+			]
+		},
+		"lines": [
+			{
+				"i": 1,
+				"quantity": "10",
+				"item": {
+					"name": "Softwarové poradenství",
+					"price": "1500.00"
+				},
+				"sum": "15000.00",
+				"taxes": [
+					{
+						"cat": "VAT",
+						"key": "standard",
+						"rate": "general",
+						"percent": "21.0%"
+					}
+				],
+				"total": "15000.00"
+			},
+			{
+				"i": 2,
+				"quantity": "5",
+				"item": {
+					"name": "Knihy",
+					"price": "250.00"
+				},
+				"sum": "1250.00",
+				"taxes": [
+					{
+						"cat": "VAT",
+						"key": "standard",
+						"rate": "reduced",
+						"percent": "12.0%"
+					}
+				],
+				"total": "1250.00"
+			}
+		],
+		"totals": {
+			"sum": "16250.00",
+			"total": "16250.00",
+			"taxes": {
+				"categories": [
+					{
+						"code": "VAT",
+						"rates": [
+							{
+								"key": "standard",
+								"base": "15000.00",
+								"percent": "21.0%",
+								"amount": "3150.00"
+							},
+							{
+								"key": "standard",
+								"base": "1250.00",
+								"percent": "12.0%",
+								"amount": "150.00"
+							}
+						],
+						"amount": "3300.00"
+					}
+				],
+				"sum": "3300.00"
+			},
+			"tax": "3300.00",
+			"total_with_tax": "19550.00",
+			"payable": "19550.00"
+		}
+	}
+}
\ No newline at end of file
diff --git a/regimes/cz/bill_invoices.go b/regimes/cz/bill_invoices.go
new file mode 100644
index 000000000..1dc54ce37
--- /dev/null
+++ b/regimes/cz/bill_invoices.go
@@ -0,0 +1,45 @@
+package cz
+
+import (
+	"fmt"
+
+	"github.com/invopop/gobl/bill"
+	"github.com/invopop/gobl/org"
+	"github.com/invopop/gobl/rules"
+	"github.com/invopop/gobl/rules/is"
+	"github.com/invopop/gobl/tax"
+)
+
+// billInvoiceRules defines Czech invoice validation rules.
+// Supplier must have either a DIČ (tax ID) or IČO (business registration).
+func billInvoiceRules() *rules.Set {
+	return rules.For(new(bill.Invoice),
+		rules.When(
+			is.InContext(tax.RegimeIn(CountryCode)),
+			rules.Field("supplier",
+				rules.Assert("01", fmt.Sprintf("invoice CZ supplier must have either tax ID code or identity with '%s' key", IdentityKeyICO),
+					is.Func(
+						fmt.Sprintf("has tax ID code or identity with '%s' key", IdentityKeyICO),
+						hasTaxIDOrIdentity,
+					),
+				),
+			),
+		),
+	)
+}
+
+func hasTaxIDOrIdentity(value any) bool {
+	party, _ := value.(*org.Party)
+	return hasTaxIDCode(party) || hasIdentityICO(party)
+}
+
+func hasTaxIDCode(party *org.Party) bool {
+	return party != nil && party.TaxID != nil && party.TaxID.Code != ""
+}
+
+func hasIdentityICO(party *org.Party) bool {
+	if party == nil || len(party.Identities) == 0 {
+		return false
+	}
+	return org.IdentityForKey(party.Identities, IdentityKeyICO) != nil
+}
diff --git a/regimes/cz/bill_invoices_test.go b/regimes/cz/bill_invoices_test.go
new file mode 100644
index 000000000..c42d1bd36
--- /dev/null
+++ b/regimes/cz/bill_invoices_test.go
@@ -0,0 +1,87 @@
+package cz_test
+
+import (
+	"testing"
+
+	"github.com/invopop/gobl/bill"
+	"github.com/invopop/gobl/num"
+	"github.com/invopop/gobl/org"
+	"github.com/invopop/gobl/regimes/cz"
+	"github.com/invopop/gobl/rules"
+	"github.com/invopop/gobl/tax"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func validInvoice() *bill.Invoice {
+	return &bill.Invoice{
+		Regime: tax.WithRegime("CZ"),
+		Series: "TEST",
+		Code:   "0002",
+		Supplier: &org.Party{
+			Name: "Test Supplier",
+			TaxID: &tax.Identity{
+				Country: "CZ",
+				Code:    "00177041",
+			},
+		},
+		Customer: &org.Party{
+			Name: "Test Customer",
+			TaxID: &tax.Identity{
+				Country: "CZ",
+				Code:    "45274649",
+			},
+		},
+		Lines: []*bill.Line{
+			{
+				Quantity: num.MakeAmount(1, 0),
+				Item: &org.Item{
+					Name:  "bogus",
+					Price: num.NewAmount(10000, 2),
+					Unit:  org.UnitPackage,
+				},
+				Taxes: tax.Set{
+					{
+						Category: "VAT",
+						Rate:     "standard",
+					},
+				},
+			},
+		},
+	}
+}
+
+func TestInvoiceValidation(t *testing.T) {
+	t.Run("valid invoice with tax ID", func(t *testing.T) {
+		inv := validInvoice()
+		require.NoError(t, inv.Calculate())
+		assert.NoError(t, rules.Validate(inv))
+	})
+
+	t.Run("valid invoice with IČO instead of tax ID", func(t *testing.T) {
+		inv := validInvoice()
+		inv.Supplier.TaxID = nil
+		inv.Supplier.Identities = []*org.Identity{
+			{
+				Key:  cz.IdentityKeyICO,
+				Code: "00177041",
+			},
+		}
+		require.NoError(t, inv.Calculate())
+		assert.NoError(t, rules.Validate(inv))
+	})
+
+	t.Run("missing both tax ID and IČO", func(t *testing.T) {
+		inv := validInvoice()
+		inv.Supplier.TaxID = nil
+		require.NoError(t, inv.Calculate())
+		assert.ErrorContains(t, rules.Validate(inv), "[GOBL-CZ-BILL-INVOICE-01]")
+	})
+
+	t.Run("invalid supplier tax ID code", func(t *testing.T) {
+		inv := validInvoice()
+		inv.Supplier.TaxID.Code = "00177042"
+		require.NoError(t, inv.Calculate())
+		assert.ErrorContains(t, rules.Validate(inv), "[GOBL-CZ-TAX-IDENTITY-01]")
+	})
+}
diff --git a/regimes/cz/cz.go b/regimes/cz/cz.go
new file mode 100644
index 000000000..b8ef13b3a
--- /dev/null
+++ b/regimes/cz/cz.go
@@ -0,0 +1,79 @@
+// Package cz provides a regime definition for the Czech Republic.
+package cz
+
+import (
+	"github.com/invopop/gobl/bill"
+	"github.com/invopop/gobl/cbc"
+	"github.com/invopop/gobl/currency"
+	"github.com/invopop/gobl/i18n"
+	"github.com/invopop/gobl/org"
+	"github.com/invopop/gobl/pkg/here"
+	"github.com/invopop/gobl/rules"
+	"github.com/invopop/gobl/tax"
+)
+
+// CountryCode is the ISO 3166-1 alpha-2 code for the Czech Republic.
+const CountryCode = "CZ"
+
+func init() {
+	tax.RegisterRegimeDef(New())
+	rules.Register("cz", rules.GOBL.Add(CountryCode),
+		billInvoiceRules(),
+		orgIdentityRules(),
+		taxIdentityRules(),
+	)
+}
+
+// New instantiates a new Czech Republic regime.
+func New() *tax.RegimeDef {
+	return &tax.RegimeDef{
+		Country:   CountryCode,
+		Currency:  currency.CZK,
+		TaxScheme: tax.CategoryVAT,
+		Name: i18n.String{
+			i18n.EN: "Czech Republic",
+			i18n.CS: "Česká republika",
+		},
+		Description: i18n.String{
+			i18n.EN: here.Doc(`
+				The Czech Republic's tax system is administered by the Financial
+				Administration of the Czech Republic (Finanční správa ČR). As an EU member
+				state, the Czech Republic follows the EU VAT Directive.
+
+				VAT (DPH — Daň z přidané hodnoty) applies at a standard rate of 21% and a
+				single reduced rate of 12% (since January 2024, when the previous first
+				reduced rate of 15% and second reduced rate of 10% were merged). Certain
+				supplies are zero-rated (e.g. exports) or exempt (e.g. healthcare,
+				education, financial services).
+
+				Businesses are identified by their DIČ (Daňové identifikační číslo), which
+				consists of the prefix CZ followed by 8 to 10 digits. For legal entities
+				the DIČ is 8 digits with a modulo-11 checksum; for individuals it is
+				derived from the birth number (Rodné číslo) and is 9 or 10 digits.
+			`),
+		},
+		TimeZone:   "Europe/Prague",
+		Identities: identityDefinitions,
+		Categories: taxCategories,
+		Corrections: []*tax.CorrectionDefinition{
+			{
+				Schema: bill.ShortSchemaInvoice,
+				Types: []cbc.Key{
+					bill.InvoiceTypeCreditNote,
+					bill.InvoiceTypeDebitNote,
+				},
+			},
+		},
+		Normalizer: Normalize,
+	}
+}
+
+// Normalize will perform any regime specific normalization.
+func Normalize(doc any) {
+	switch obj := doc.(type) {
+	case *tax.Identity:
+		tax.NormalizeIdentity(obj)
+	case *org.Identity:
+		normalizeIdentity(obj)
+	}
+}
diff --git a/regimes/cz/org_identities.go b/regimes/cz/org_identities.go
new file mode 100644
index 000000000..33105132b
--- /dev/null
+++ b/regimes/cz/org_identities.go
@@ -0,0 +1,61 @@
+package cz
+
+import (
+	"github.com/invopop/gobl/cbc"
+	"github.com/invopop/gobl/i18n"
+	"github.com/invopop/gobl/org"
+	"github.com/invopop/gobl/rules"
+	"github.com/invopop/gobl/rules/is"
+)
+
+const (
+	// IdentityKeyICO represents the Czech business registration number
+	// (Identifikační číslo osoby) assigned to all businesses at formation.
+	// For international trade, the DIČ (VAT number) should be used via
+	// the TaxID field instead.
+	IdentityKeyICO cbc.Key = "cz-ico"
+)
+
+var identityDefinitions = []*cbc.Definition{
+	{
+		Key: IdentityKeyICO,
+		Name: i18n.String{
+			i18n.EN: "Business Registration Number",
+			i18n.CS: "Identifikační číslo osoby",
+		},
+	},
+}
+
+func orgIdentityRules() *rules.Set {
+	return rules.For(new(org.Identity),
+		rules.When(
+			is.Func("is IČO", isICOIdentity),
+			rules.Field("code",
+				rules.AssertIfPresent("01", "invalid Czech IČO code",
+					is.Func("valid", isValidICOCode),
+				),
+			),
+		),
+	)
+}
+
+func isICOIdentity(val any) bool {
+	id, _ := val.(*org.Identity)
+	return id != nil && id.Key == IdentityKeyICO
+}
+
+func isValidICOCode(val any) bool {
+	code, _ := val.(cbc.Code)
+	if code == "" || len(code.String()) != 8 {
+		return false
+	}
+	return validateLegalEntityCode(code.String()) == nil
+}
+
+// normalizeIdentity normalizes IČO codes by stripping non-numeric characters.
+func normalizeIdentity(id *org.Identity) {
+	if id == nil || id.Key != IdentityKeyICO {
+		return
+	}
+	id.Code = cbc.NormalizeNumericalCode(id.Code)
+}
diff --git a/regimes/cz/org_identities_test.go b/regimes/cz/org_identities_test.go
new file mode 100644
index 000000000..b1c49de6d
--- /dev/null
+++ b/regimes/cz/org_identities_test.go
@@ -0,0 +1,56 @@
+package cz_test
+
+import (
+	"testing"
+
+	"github.com/invopop/gobl/org"
+	"github.com/invopop/gobl/regimes/cz"
+	"github.com/invopop/gobl/rules"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestOrgIdentityRules(t *testing.T) {
+	tests := []struct {
+		name     string
+		identity *org.Identity
+		err      string
+	}{
+		{
+			name:     "valid IČO - Škoda Auto",
+			identity: &org.Identity{Key: cz.IdentityKeyICO, Code: "00177041"},
+		},
+		{
+			name:     "valid IČO - ČEZ",
+			identity: &org.Identity{Key: cz.IdentityKeyICO, Code: "45274649"},
+		},
+		{
+			name:     "valid IČO - Komerční banka",
+			identity: &org.Identity{Key: cz.IdentityKeyICO, Code: "45317054"},
+		},
+		{
+			name:     "invalid IČO checksum",
+			identity: &org.Identity{Key: cz.IdentityKeyICO, Code: "00177042"},
+			err:      "[GOBL-CZ-ORG-IDENTITY-01]",
+		},
+		{
+			name:     "invalid IČO too short",
+			identity: &org.Identity{Key: cz.IdentityKeyICO, Code: "0017704"},
+			err:      "[GOBL-CZ-ORG-IDENTITY-01]",
+		},
+		{
+			name:     "non-IČO identity ignored",
+			identity: &org.Identity{Key: "other", Code: "anything"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := rules.Validate(tt.identity)
+			if tt.err == "" {
+				assert.NoError(t, err)
+			} else {
+				assert.ErrorContains(t, err, tt.err)
+			}
+		})
+	}
+}
diff --git a/regimes/cz/tax_categories.go b/regimes/cz/tax_categories.go
new file mode 100644
index 000000000..9003d2423
--- /dev/null
+++ b/regimes/cz/tax_categories.go
@@ -0,0 +1,113 @@
+package cz
+
+import (
+	"github.com/invopop/gobl/cal"
+	"github.com/invopop/gobl/cbc"
+	"github.com/invopop/gobl/i18n"
+	"github.com/invopop/gobl/num"
+	"github.com/invopop/gobl/tax"
+)
+
+var taxCategories = []*tax.CategoryDef{
+	{
+		Code: tax.CategoryVAT,
+		Name: i18n.String{
+			i18n.EN: "VAT",
+			i18n.CS: "DPH",
+		},
+		Title: i18n.String{
+			i18n.EN: "Value Added Tax",
+			i18n.CS: "Daň z přidané hodnoty",
+		},
+		Keys: tax.GlobalVATKeys(),
+		Rates: []*tax.RateDef{
+			// Standard rate
+			{
+				Keys: []cbc.Key{tax.KeyStandard},
+				Rate: tax.RateGeneral,
+				Name: i18n.String{
+					i18n.EN: "Standard Rate",
+					i18n.CS: "Základní sazba",
+				},
+				Values: []*tax.RateValueDef{
+					{
+						Percent: num.MakePercentage(210, 3),
+						Since:   cal.NewDate(2013, 1, 1),
+					},
+					{
+						Percent: num.MakePercentage(200, 3),
+						Since:   cal.NewDate(2010, 1, 1),
+					},
+					{
+						Percent: num.MakePercentage(190, 3),
+						Since:   cal.NewDate(2004, 5, 1),
+					},
+				},
+			},
+			// Reduced rate (merged from two reduced rates in 2024)
+			{
+				Keys: []cbc.Key{tax.KeyStandard},
+				Rate: tax.RateReduced,
+				Name: i18n.String{
+					i18n.EN: "Reduced Rate",
+					i18n.CS: "Snížená sazba",
+				},
+				Values: []*tax.RateValueDef{
+					{
+						Percent: num.MakePercentage(120, 3),
+						Since:   cal.NewDate(2024, 1, 1),
+					},
+					{
+						Percent: num.MakePercentage(150, 3),
+						Since:   cal.NewDate(2013, 1, 1),
+					},
+					{
+						Percent: num.MakePercentage(140, 3),
+						Since:   cal.NewDate(2012, 1, 1),
+					},
+					{
+						Percent: num.MakePercentage(100, 3),
+						Since:   cal.NewDate(2010, 1, 1),
+					},
+					{
+						Percent: num.MakePercentage(90, 3),
+						Since:   cal.NewDate(2008, 1, 1),
+					},
+					{
+						Percent: num.MakePercentage(50, 3),
+						Since:   cal.NewDate(2004, 5, 1),
+					},
+				},
+			},
+			// Second reduced rate (abolished 2024-01-01, merged into single 12% reduced rate)
+			{
+				Keys: []cbc.Key{tax.KeyStandard},
+				Rate: tax.RateSuperReduced,
+				Name: i18n.String{
+					i18n.EN: "Second Reduced Rate",
+					i18n.CS: "Druhá snížená sazba",
+				},
+				Values: []*tax.RateValueDef{
+					{
+						Percent: num.MakePercentage(100, 3),
+						Since:   cal.NewDate(2015, 1, 1),
+					},
+				},
+			},
+		},
+		Sources: []*cbc.Source{
+			{
+				Title: i18n.String{
+					i18n.EN: "Czech Republic - General rules and VAT rates",
+				},
+				URL: "https://portal.gov.cz/en/informace/general-rules-and-vat-rates-INF-205",
+			},
+			{
+				Title: i18n.String{
+					i18n.EN: "Registering for VAT in the Czech Republic",
+				},
+				URL: "https://portal.gov.cz/en/informace/registering-for-vat-INF-204",
+			},
+		},
+	},
+}
diff --git a/regimes/cz/tax_identity.go b/regimes/cz/tax_identity.go
new file mode 100644
index 000000000..fc78dddcb
--- /dev/null
+++ b/regimes/cz/tax_identity.go
@@ -0,0 +1,110 @@
+package cz
+
+import (
+	"errors"
+	"regexp"
+	"strconv"
+
+	"github.com/invopop/gobl/cbc"
+	"github.com/invopop/gobl/rules"
+	"github.com/invopop/gobl/rules/is"
+	"github.com/invopop/gobl/tax"
+)
+
+// Reference: https://arthurdejong.org/python-stdnum/doc/1.17/stdnum.cz.dic
+
+var taxCodeRegexps = []*regexp.Regexp{
+	regexp.MustCompile(`^\d{8,10}$`),
+}
+
+func taxIdentityRules() *rules.Set {
+	return rules.For(new(tax.Identity),
+		rules.When(tax.IdentityIn(CountryCode),
+			rules.Field("code",
+				rules.AssertIfPresent("01", "invalid Czech DIČ code",
+					is.Func("valid", isValidTaxIdentityCode),
+				),
+			),
+		),
+	)
+}
+
+func isValidTaxIdentityCode(value any) bool {
+	code, ok := value.(cbc.Code)
+	if !ok || code == "" {
+		return false
+	}
+	return validateTaxCode(code) == nil
+}
+
+func validateTaxCode(value any) error {
+	code, ok := value.(cbc.Code)
+	if !ok || code == "" {
+		return nil
+	}
+	val := code.String()
+
+	match := false
+	for _, re := range taxCodeRegexps {
+		if re.MatchString(val) {
+			match = true
+			break
+		}
+	}
+	if !match {
+		return errors.New("invalid format")
+	}
+
+	switch len(val) {
+	case 8:
+		return validateLegalEntityCode(val)
+	case 9:
+		// 9-digit codes include special IDs (starting with 6) and
+		// older individual birth number formats; no checksum required.
+		return nil
+	case 10:
+		return validateIndividualCode(val)
+	}
+
+	return nil
+}
+
+// validateLegalEntityCode validates an 8-digit legal entity DIČ using
+// modulo-11 checksum with weights [8,7,6,5,4,3,2].
+func validateLegalEntityCode(val string) error {
+	weights := []int{8, 7, 6, 5, 4, 3, 2}
+	total := 0
+
+	for i := range 7 {
+		total += int(val[i]-'0') * weights[i]
+	}
+
+	expected := 11 - (total % 11)
+	if expected == 10 {
+		expected = 0
+	} else if expected == 11 {
+		expected = 1
+	}
+
+	checkDigit := int(val[7] - '0')
+	if checkDigit != expected {
+		return errors.New("checksum mismatch")
+	}
+
+	return nil
+}
+
+// validateIndividualCode validates a 10-digit individual DIČ (derived from
+// Rodné číslo). Must be divisible by 11.
+func validateIndividualCode(val string) error {
+	n, err := strconv.ParseUint(val, 10, 64)
+	if err != nil {
+		return errors.New("invalid format")
+	}
+
+	if n%11 != 0 {
+		return errors.New("checksum mismatch")
+	}
+
+	return nil
+}
diff --git a/regimes/cz/tax_identity_test.go b/regimes/cz/tax_identity_test.go
new file mode 100644
index 000000000..9808b3375
--- /dev/null
+++ b/regimes/cz/tax_identity_test.go
@@ -0,0 +1,97 @@
+package cz_test
+
+import (
+	"testing"
+
+	"github.com/invopop/gobl/cbc"
+	"github.com/invopop/gobl/regimes/cz"
+	"github.com/invopop/gobl/rules"
+	"github.com/invopop/gobl/tax"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNormalizeTaxIdentity(t *testing.T) {
+	tests := []struct {
+		Code     cbc.Code
+		Expected cbc.Code
+	}{
+		{Code: "00177041", Expected: "00177041"},
+		{Code: "CZ00177041", Expected: "00177041"},
+		{Code: "001 770 41", Expected: "00177041"},
+		{Code: "001-770-41", Expected: "00177041"},
+	}
+	for _, ts := range tests {
+		tID := &tax.Identity{Country: "CZ", Code: ts.Code}
+		cz.Normalize(tID)
+		assert.Equal(t, ts.Expected, tID.Code)
+	}
+}
+
+func TestTaxIdentityRules(t *testing.T) {
+	tests := []struct {
+		name string
+		code cbc.Code
+		err  string
+	}{
+		// Valid legal entity codes (8 digits)
+		{name: "valid legal entity - Škoda Auto", code: "00177041"},
+		{name: "valid legal entity - ČEZ", code: "45274649"},
+		{name: "valid legal entity", code: "25596641"},
+		{name: "valid legal entity - T-Mobile CZ", code: "64949681"},
+		{name: "valid legal entity - Komerční banka", code: "45317054"},
+		// Valid individual code (10 digits, divisible by 11)
+		{name: "valid individual", code: "7103192745"},
+		// Valid legal entity with check digit 0 (expected == 10 branch)
+		{name: "valid legal entity check digit 0", code: "00200000"},
+		// Valid 9-digit codes
+		{name: "valid 9-digit special", code: "612345679"},
+		{name: "valid 9-digit individual", code: "710319274"},
+		// Invalid format
+		{
+			name: "too short",
+			code: "0017704",
+			err:  "IDENTITY-01",
+		},
+		{
+			name: "too long",
+			code: "00177041234",
+			err:  "IDENTITY-01",
+		},
+		{
+			name: "contains letters",
+			code: "0017704A",
+			err:  "IDENTITY-01",
+		},
+		// Bad checksum - legal entity
+		{
+			name: "bad checksum legal entity",
+			code: "00177042",
+			err:  "IDENTITY-01",
+		},
+		{
+			name: "bad checksum legal entity 2",
+			code: "45274640",
+			err:  "IDENTITY-01",
+		},
+		// Bad checksum - individual (10 digits, not divisible by 11)
+		{
+			name: "bad checksum individual",
+			code: "7103192746",
+			err:  "IDENTITY-01",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tID := &tax.Identity{Country: "CZ", Code: tt.code}
+			err := rules.Validate(tID)
+			if tt.err == "" {
+				assert.NoError(t, err)
+			} else {
+				if assert.Error(t, err) {
+					assert.Contains(t, err.Error(), tt.err)
+				}
+			}
+		})
+	}
+}
diff --git a/regimes/regimes.go b/regimes/regimes.go
index ff3cb73a8..58ebd6c2a 100644
--- a/regimes/regimes.go
+++ b/regimes/regimes.go
@@ -13,6 +13,7 @@ import (
 	_ "github.com/invopop/gobl/regimes/ca"
 	_ "github.com/invopop/gobl/regimes/ch"
 	_ "github.com/invopop/gobl/regimes/co"
+	_ "github.com/invopop/gobl/regimes/cz"
 	_ "github.com/invopop/gobl/regimes/de"
 	_ "github.com/invopop/gobl/regimes/dk"
 	_ "github.com/invopop/gobl/regimes/es"