diff --git a/litellm/utils.py b/litellm/utils.py
index 18b89ee0d13..62eaaf266ec 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -6139,6 +6139,11 @@ def validate_environment(
                 keys_in_environment = True
             else:
                 missing_keys.append("MOONSHOT_API_KEY")
+        elif custom_llm_provider == "zai":
+            if "ZAI_API_KEY" in os.environ:
+                keys_in_environment = True
+            else:
+                missing_keys.append("ZAI_API_KEY")
     else:
         ## openai - chatcompletion + text completion
         if (
diff --git a/tests/test_litellm/test_utils.py b/tests/test_litellm/test_utils.py
index 26ae6ff7f4c..426696287d3 100644
--- a/tests/test_litellm/test_utils.py
+++ b/tests/test_litellm/test_utils.py
@@ -4710,3 +4710,21 @@ class TestValidateEnvironmentTencent:
         assert "TENCENT_API_KEY" in result["missing_keys"]
 
 
+class TestValidateEnvironmentZai:
+    """Tests that validate_environment resolves ZAI_API_KEY for the zai provider."""
+
+    def test_reports_key_present(self):
+        with patch.dict(os.environ, {"ZAI_API_KEY": "sk-zai"}):
+            result = litellm.validate_environment(model="zai/glm-5.1")
+
+        assert result["keys_in_environment"] is True
+        assert result["missing_keys"] == []
+
+    def test_reports_key_missing(self):
+        with patch.dict(os.environ, {}, clear=True):
+            result = litellm.validate_environment(model="zai/glm-5.1")
+
+        assert result["keys_in_environment"] is False
+        assert "ZAI_API_KEY" in result["missing_keys"]
+
+