diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 9e2828eaf098c..100233d95a5f1 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -259,6 +259,19 @@ libc_support_library(
     hdrs = ["hdr/unistd_overlay.h"],
 )
 
+libc_support_library(
+    name = "hdr_wchar_macros",
+    hdrs = ["hdr/wchar_macros.h"],
+    deps = [
+        ":hdr_wchar_overlay",
+    ],
+)
+
+libc_support_library(
+    name = "hdr_wchar_overlay",
+    hdrs = ["hdr/wchar_overlay.h"],
+)
+
 ############################ Type Proxy Header Files ###########################
 
 libc_support_library(
@@ -423,6 +436,22 @@ libc_support_library(
     hdrs = ["hdr/types/struct_msghdr.h"],
 )
 
+libc_support_library(
+    name = "types_wchar_t",
+    hdrs = ["hdr/types/wchar_t.h"],
+    deps = [
+        ":hdr_wchar_overlay",
+    ],
+)
+
+libc_support_library(
+    name = "types_wint_t",
+    hdrs = ["hdr/types/wint_t.h"],
+    deps = [
+        ":hdr_wchar_overlay",
+    ],
+)
+
 ############################### Support libraries ##############################
 
 libc_support_library(
@@ -1636,6 +1665,16 @@ libc_support_library(
     ],
 )
 
+libc_support_library(
+    name = "__support_wctype_utils",
+    hdrs = ["src/__support/wctype_utils.h"],
+    deps = [
+        ":__support_cpp_optional",
+        ":__support_macros_attributes",
+        ":__support_macros_config",
+    ],
+)
+
 ########################## externally shared targets ###########################
 
 libc_header_library(
@@ -5676,3 +5715,276 @@ libc_function(
         ":types_struct_timespec",
     ],
 )
+
+############################## wchar targets ###############################
+
+libc_function(
+    name = "btowc",
+    srcs = ["src/wchar/btowc.cpp"],
+    hdrs = ["src/wchar/btowc.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":__support_wctype_utils",
+        ":hdr_wchar_macros",
+        ":types_wint_t",
+    ],
+)
+
+libc_function(
+    name = "wcpcpy",
+    srcs = ["src/wchar/wcpcpy.cpp"],
+    hdrs = ["src/wchar/wcpcpy.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":string_utils",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcpncpy",
+    srcs = ["src/wchar/wcpncpy.cpp"],
+    hdrs = ["src/wchar/wcpncpy.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":__support_macros_null_check",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcscat",
+    srcs = ["src/wchar/wcscat.cpp"],
+    hdrs = ["src/wchar/wcscat.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":string_utils",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcschr",
+    srcs = ["src/wchar/wcschr.cpp"],
+    hdrs = ["src/wchar/wcschr.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcscmp",
+    srcs = ["src/wchar/wcscmp.cpp"],
+    hdrs = ["src/wchar/wcscmp.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_null_check",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcscpy",
+    srcs = ["src/wchar/wcscpy.cpp"],
+    hdrs = ["src/wchar/wcscpy.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":string_utils",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcslen",
+    srcs = ["src/wchar/wcslen.cpp"],
+    hdrs = ["src/wchar/wcslen.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":string_utils",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcsncat",
+    srcs = ["src/wchar/wcsncat.cpp"],
+    hdrs = ["src/wchar/wcsncat.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":string_utils",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcsncmp",
+    srcs = ["src/wchar/wcsncmp.cpp"],
+    hdrs = ["src/wchar/wcsncmp.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_null_check",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcsncpy",
+    srcs = ["src/wchar/wcsncpy.cpp"],
+    hdrs = ["src/wchar/wcsncpy.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcspbrk",
+    srcs = ["src/wchar/wcspbrk.cpp"],
+    hdrs = ["src/wchar/wcspbrk.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_null_check",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcsrchr",
+    srcs = ["src/wchar/wcsrchr.cpp"],
+    hdrs = ["src/wchar/wcsrchr.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":__support_macros_null_check",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcsspn",
+    srcs = ["src/wchar/wcsspn.cpp"],
+    hdrs = ["src/wchar/wcsspn.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wcsstr",
+    srcs = ["src/wchar/wcsstr.cpp"],
+    hdrs = ["src/wchar/wcsstr.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":string_utils",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wctob",
+    srcs = ["src/wchar/wctob.cpp"],
+    hdrs = ["src/wchar/wctob.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":__support_macros_null_check",
+        ":__support_wctype_utils",
+        ":hdr_stdio_macros",
+        ":types_wint_t",
+    ],
+)
+
+libc_function(
+    name = "wmemchr",
+    srcs = ["src/wchar/wmemchr.cpp"],
+    hdrs = ["src/wchar/wmemchr.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wmemcmp",
+    srcs = ["src/wchar/wmemcmp.cpp"],
+    hdrs = ["src/wchar/wmemcmp.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":__support_macros_null_check",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wmemcpy",
+    srcs = ["src/wchar/wmemcpy.cpp"],
+    hdrs = ["src/wchar/wmemcpy.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wmemmove",
+    srcs = ["src/wchar/wmemmove.cpp"],
+    hdrs = ["src/wchar/wmemmove.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_null_check",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wmempcpy",
+    srcs = ["src/wchar/wmempcpy.cpp"],
+    hdrs = ["src/wchar/wmempcpy.h"],
+    deps = [
+        ":__support_common",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
+libc_function(
+    name = "wmemset",
+    srcs = ["src/wchar/wmemset.cpp"],
+    hdrs = ["src/wchar/wmemset.h"],
+    deps = [
+        ":__support_common",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
diff --git a/utils/bazel/llvm-project-overlay/libc/test/src/wchar/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/test/src/wchar/BUILD.bazel
new file mode 100644
index 0000000000000..25243ae7c2b45
--- /dev/null
+++ b/utils/bazel/llvm-project-overlay/libc/test/src/wchar/BUILD.bazel
@@ -0,0 +1,214 @@
+# This file is licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+# Tests for LLVM libc wchar.h functions.
+
+load("//libc/test:libc_test_rules.bzl", "libc_test")
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+libc_test(
+    name = "btowc_test",
+    srcs = ["btowc_test.cpp"],
+    deps = [
+        "//libc:btowc",
+        "//libc:hdr_wchar_macros",
+    ],
+)
+
+libc_test(
+    name = "wcpcpy_test",
+    srcs = ["wcpcpy_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcpcpy",
+    ],
+)
+
+libc_test(
+    name = "wcpncpy_test",
+    srcs = ["wcpncpy_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcpncpy",
+    ],
+)
+
+libc_test(
+    name = "wcscat_test",
+    srcs = ["wcscat_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcscat",
+    ],
+)
+
+libc_test(
+    name = "wcschr_test",
+    srcs = ["wcschr_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcschr",
+    ],
+)
+
+libc_test(
+    name = "wcscmp_test",
+    srcs = ["wcscmp_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcscmp",
+    ],
+)
+
+libc_test(
+    name = "wcscpy_test",
+    srcs = ["wcscpy_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcscpy",
+    ],
+)
+
+libc_test(
+    name = "wcslen_test",
+    srcs = ["wcslen_test.cpp"],
+    deps = [
+        "//libc:types_size_t",
+        "//libc:types_wchar_t",
+        "//libc:wcslen",
+    ],
+)
+
+libc_test(
+    name = "wcsncat_test",
+    srcs = ["wcsncat_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcsncat",
+    ],
+)
+
+libc_test(
+    name = "wcsncmp_test",
+    srcs = ["wcsncmp_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcsncmp",
+    ],
+)
+
+libc_test(
+    name = "wcsncpy_test",
+    srcs = ["wcsncpy_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcsncpy",
+    ],
+)
+
+libc_test(
+    name = "wcsrchr_test",
+    srcs = ["wcsrchr_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcsrchr",
+    ],
+)
+
+libc_test(
+    name = "wcspbrk_test",
+    srcs = ["wcspbrk_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcspbrk",
+    ],
+)
+
+libc_test(
+    name = "wcsspn_test",
+    srcs = ["wcsspn_test.cpp"],
+    deps = [
+        "//libc:types_size_t",
+        "//libc:types_wchar_t",
+        "//libc:wcsspn",
+    ],
+)
+
+libc_test(
+    name = "wcsstr_test",
+    srcs = ["wcsstr_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wcsstr",
+    ],
+)
+
+libc_test(
+    name = "wctob_test",
+    srcs = ["wctob_test.cpp"],
+    deps = [
+        "//libc:hdr_stdio_macros",
+        "//libc:wctob",
+    ],
+)
+
+libc_test(
+    name = "wmemchr_test",
+    srcs = ["wmemchr_test.cpp"],
+    deps = [
+        "//libc:types_wchar_t",
+        "//libc:wmemchr",
+    ],
+)
+
+libc_test(
+    name = "wmemcmp_test",
+    srcs = ["wmemcmp_test.cpp"],
+    deps = [
+        "//libc:types_size_t",
+        "//libc:types_wchar_t",
+        "//libc:wmemcmp",
+    ],
+)
+
+libc_test(
+    name = "wmemcpy_test",
+    srcs = ["wmemcpy_test.cpp"],
+    deps = [
+        "//libc:types_size_t",
+        "//libc:types_wchar_t",
+        "//libc:wmemcpy",
+    ],
+)
+
+libc_test(
+    name = "wmemmove_test",
+    srcs = ["wmemmove_test.cpp"],
+    deps = [
+        "//libc:types_size_t",
+        "//libc:types_wchar_t",
+        "//libc:wmemmove",
+    ],
+)
+
+libc_test(
+    name = "wmempcpy_test",
+    srcs = ["wmempcpy_test.cpp"],
+    deps = [
+        "//libc:wmempcpy",
+    ],
+)
+
+libc_test(
+    name = "wmemset_test",
+    srcs = ["wmemset_test.cpp"],
+    deps = [
+        "//libc:types_size_t",
+        "//libc:types_wchar_t",
+        "//libc:wmemset",
+    ],
+)