diff --git a/awx_collection/plugins/modules/project.py b/awx_collection/plugins/modules/project.py
index ed0d475b1481..b093e4f9bc59 100644
--- a/awx_collection/plugins/modules/project.py
+++ b/awx_collection/plugins/modules/project.py
@@ -247,6 +247,18 @@ def wait_for_project_update(module, last_request):
 
 
 def main():
+    """Entry point for the project module.
+
+    Builds the argument spec, resolves related resources (organization,
+    execution environment, credential, signature_validation_credential,
+    notification templates), and creates, updates, or deletes the
+    Automation Platform Controller project accordingly.
+
+    For credential and signature_validation_credential specifically: an
+    empty string ("") is treated as an explicit request to clear the
+    field, mapping it to None instead of attempting (and failing) to
+    resolve a credential literally named "".
+    """
     # Any additional arguments that are not fields of the item can be added here
     argument_spec = dict(
         name=dict(required=True),
@@ -383,7 +395,7 @@ def main():
         (signature_validation_credential, 'signature_validation_credential', 'credentials'),
     ):
         if variable is not None:
-            project_fields[field] = module.resolve_name_to_id(endpoint, variable)
+            project_fields[field] = module.resolve_name_to_id(endpoint, variable) if variable else None
 
     if org_id is not None:
         # this is resolved earlier, so save an API call and don't do it again in the loop above
diff --git a/awx_collection/test/awx/test_project.py b/awx_collection/test/awx/test_project.py
index 27b7b96e05d6..d565dc1950b5 100644
--- a/awx_collection/test/awx/test_project.py
+++ b/awx_collection/test/awx/test_project.py
@@ -66,3 +66,40 @@ def test_create_project_copy_from(run_module, admin_user, organization, silence_
         admin_user,
     )
     silence_warning.assert_called_with("A project with the name {0} already exists.".format(proj_name))
+
+
+@pytest.mark.django_db
+def test_clear_project_credential(run_module, admin_user, organization, scm_credential):
+    result = run_module(
+        'project',
+        dict(
+            name='foo',
+            organization=organization.name,
+            scm_type='git',
+            scm_url='https://foo.invalid',
+            credential=scm_credential.name,
+            wait=False,
+        ),
+        admin_user,
+    )
+    assert result.pop('changed', None), result
+
+    proj = Project.objects.get(name='foo')
+    assert proj.credential_id == scm_credential.id
+
+    result = run_module(
+        'project',
+        dict(
+            name='foo',
+            organization=organization.name,
+            scm_type='git',
+            scm_url='https://foo.invalid',
+            credential='',
+            wait=False,
+        ),
+        admin_user,
+    )
+    assert result.pop('changed', None), result
+
+    proj.refresh_from_db()
+    assert proj.credential_id is None