diff --git a/src/openklant/utils/tests/test_validators.py b/src/openklant/utils/tests/test_validators.py
index 143dc9d5..dd316f3c 100644
--- a/src/openklant/utils/tests/test_validators.py
+++ b/src/openklant/utils/tests/test_validators.py
@@ -7,6 +7,7 @@
     validate_no_space,
     validate_phone_number,
     validate_postal_code,
+    validate_country,
 )
 
 
@@ -147,3 +148,22 @@ def test_validate_iban(self):
         self.assertIsNone(validate_iban("ab1299999999999"))
         self.assertIsNone(validate_iban("ab129"))
         self.assertIsNone(validate_iban("ab12aaaaaaaaaa"))
+
+    def test_validate_country(self):
+        invalid_codes = [
+            "",
+            "1",
+            "10",
+            "ZZ",
+            "1Z",
+        ]
+        for code in invalid_codes:
+            self.assertRaisesMessage(
+                ValidationError,
+                "Ongeldige landcode, de code moet behoren tot de ISO 3166-standaard",
+                validate_country,
+                code,
+            )
+
+        self.assertIsNone(validate_country("NL"))
+        self.assertIsNone(validate_country("nl"))
diff --git a/src/openklant/utils/validators.py b/src/openklant/utils/validators.py
index 2f657a9c..5bca9349 100644
--- a/src/openklant/utils/validators.py
+++ b/src/openklant/utils/validators.py
@@ -14,7 +14,7 @@ def validate_country(value) -> None:
     """
     if not value.upper() in COUNTRIES_DICT.keys():
         raise ValidationError(
-            _("Ongeldige landcode, de code moet behoren tot de ISO 3166-standaard.")
+            _("Ongeldige landcode, de code moet behoren tot de ISO 3166-standaard")
         )