diff --git a/moto/resourcegroupstaggingapi/models.py b/moto/resourcegroupstaggingapi/models.py
index 657a74cdba71..07c08d087b39 100644
--- a/moto/resourcegroupstaggingapi/models.py
+++ b/moto/resourcegroupstaggingapi/models.py
@@ -613,7 +613,11 @@ def format_tag_keys(
         # VPC VPN Connection
 
         # Lambda Instance
-        if not resource_type_filters or "lambda" in resource_type_filters:
+        if (
+            not resource_type_filters
+            or "lambda" in resource_type_filters
+            or "lambda:function" in resource_type_filters
+        ):
             for f in self.lambda_backend.list_functions():
                 tags = format_tags(f.tags)
                 if not tags or not tag_filter(tags):
diff --git a/tests/test_resourcegroupstaggingapi/test_resourcegroupstaggingapi.py b/tests/test_resourcegroupstaggingapi/test_resourcegroupstaggingapi.py
index fe6ad614795a..c1bbb2b80dcb 100644
--- a/tests/test_resourcegroupstaggingapi/test_resourcegroupstaggingapi.py
+++ b/tests/test_resourcegroupstaggingapi/test_resourcegroupstaggingapi.py
@@ -704,6 +704,9 @@ def assert_response(response, expected_arns):
     resp = rtapi.get_resources(ResourceTypeFilters=["lambda"])
     assert_response(resp, [circle_arn, rectangle_arn])
 
+    resp = rtapi.get_resources(ResourceTypeFilters=["lambda:function"])
+    assert_response(resp, [circle_arn, rectangle_arn])
+
     resp = rtapi.get_resources(TagFilters=[{"Key": "Color", "Values": ["green"]}])
     assert_response(resp, [circle_arn, rectangle_arn])