diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2e494b7..07d6e45 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 
 - Process anyOf and allOf and well as oneOf https://github.com/OpenDataServices/compile-to-json-schema/issues/28
+- Can specify multiple codelist directories
+  - New param `codelist_base_directories`
+  - CLI flag can be specified multiple times
 
 ### Removed
 
diff --git a/compiletojsonschema/cli/__main__.py b/compiletojsonschema/cli/__main__.py
index 993fb33..9ef1bb9 100644
--- a/compiletojsonschema/cli/__main__.py
+++ b/compiletojsonschema/cli/__main__.py
@@ -16,6 +16,7 @@ def main():
     parser.add_argument(
         "-c",
         "--codelist-base-directory",
+        action="append",
         help="Which directory we should look in for codelists",
     )
 
@@ -24,6 +25,6 @@ def main():
     ctjs = CompileToJsonSchema(
         input_filename=args.input_file,
         set_additional_properties_false_everywhere=args.set_additional_properties_false_everywhere,
-        codelist_base_directory=args.codelist_base_directory,
+        codelist_base_directories=args.codelist_base_directory,
     )
     print(ctjs.get_as_string())
diff --git a/compiletojsonschema/compiletojsonschema.py b/compiletojsonschema/compiletojsonschema.py
index b03d6d1..b56a11c 100644
--- a/compiletojsonschema/compiletojsonschema.py
+++ b/compiletojsonschema/compiletojsonschema.py
@@ -14,6 +14,7 @@ def __init__(
         input_filename=None,
         set_additional_properties_false_everywhere=False,
         codelist_base_directory=None,
+        codelist_base_directories=[],
         input_schema=None,
     ):
         if not isinstance(input_schema, dict) and not input_filename:
@@ -23,8 +24,14 @@ def __init__(
         self.set_additional_properties_false_everywhere = (
             set_additional_properties_false_everywhere
         )
-        if codelist_base_directory:
-            self.codelist_base_directory = os.path.expanduser(codelist_base_directory)
+        if codelist_base_directories or codelist_base_directory:
+            self.codelist_base_directories = [
+                os.path.expanduser(i) for i in codelist_base_directories
+            ]
+            if codelist_base_directory:
+                self.codelist_base_directories.append(
+                    os.path.expanduser(codelist_base_directory)
+                )
         else:
             self.codelist_base_directory = os.getcwd()
 
@@ -83,24 +90,25 @@ def __process(self, source):
         if "codelist" in source and (
             "openCodelist" not in source or not source["openCodelist"]
         ):
-            filename = os.path.join(self.codelist_base_directory, source["codelist"])
-            if os.path.isfile(filename):
-                values = []
-                with open(filename) as fp:
-                    csvreader = csv.reader(fp, delimiter=",", quotechar='"')
-                    next(csvreader, None)
-                    for row in csvreader:
-                        if len(row) > 0 and row[0]:
-                            values.append(row[0])
-                if values:
-                    out["enum"] = values
-            else:
-                raise CodeListNotFoundException(
-                    "Can not find codelist: " + source["codelist"]
-                )
+            values = []
+            with open(self._get_full_filename_to_codelist(source["codelist"])) as fp:
+                csvreader = csv.reader(fp, delimiter=",", quotechar='"')
+                next(csvreader, None)
+                for row in csvreader:
+                    if len(row) > 0 and row[0]:
+                        values.append(row[0])
+            if values:
+                out["enum"] = values
 
         return out
 
+    def _get_full_filename_to_codelist(self, reference):
+        for codelist_base_directory in self.codelist_base_directories:
+            filename = os.path.join(codelist_base_directory, reference)
+            if os.path.isfile(filename):
+                return filename
+        raise CodeListNotFoundException("Can not find codelist: " + reference)
+
 
 class CodeListNotFoundException(Exception):
     pass
diff --git a/docs/cli.rst b/docs/cli.rst
index 6dc3e1f..05c6803 100644
--- a/docs/cli.rst
+++ b/docs/cli.rst
@@ -26,6 +26,11 @@ You can set the directory that is searched for codelists using the `--codelist-b
     compiletojsonschema -c data/codelists schema.json
     compiletojsonschema --codelist-base-directory data/codelists schema.json
 
+You can pass this multiple times.
+
+.. code-block:: shell-session
+
+    compiletojsonschema -c data/codelists/open -c data/codelists/closed schema.json
 
 Set additional properties false everywhere
 ------------------------------------------
diff --git a/tests/test_codelist.py b/tests/test_codelist.py
index 2c2ae38..68d8c17 100644
--- a/tests/test_codelist.py
+++ b/tests/test_codelist.py
@@ -52,6 +52,30 @@ def test_basic():
     assert out["properties"]["pet"]["enum"] == ["Dog", "Cat", "Parrot"]
 
 
+def test_multiple_dirs():
+
+    # schema.json has no openCodelist value deliberately so we can test the default options.
+    input_filename = os.path.join(
+        os.path.dirname(os.path.realpath(__file__)),
+        "fixtures",
+        "codelists",
+        "schema.json",
+    )
+
+    codelist_dir1 = os.path.join(
+        os.path.dirname(os.path.realpath(__file__)),
+        "fixtures",
+        "codelists",
+    )
+
+    ctjs = CompileToJsonSchema(
+        input_filename=input_filename, codelist_base_directories=[codelist_dir1]
+    )
+    out = ctjs.get()
+
+    assert out["properties"]["pet"]["enum"] == ["Dog", "Cat", "Parrot"]
+
+
 def test_open_codelist():
 
     input_filename = os.path.join(