diff --git a/litellm/caching/gcs_cache.py b/litellm/caching/gcs_cache.py
index 3327e094bc2f..0e6a111eb2bb 100644
--- a/litellm/caching/gcs_cache.py
+++ b/litellm/caching/gcs_cache.py
@@ -5,6 +5,7 @@
 import json
 import asyncio
 from typing import Optional
+from urllib.parse import quote
 
 from litellm._logging import print_verbose, verbose_logger
 from litellm.integrations.gcs_bucket.gcs_bucket_base import GCSBucketBase
@@ -48,7 +49,7 @@ def set_cache(self, key, value, **kwargs):
             headers = self._construct_headers()
             object_name = self.key_prefix + key
             bucket_name = self.bucket_name
-            url = f"https://storage.googleapis.com/upload/storage/v1/b/{bucket_name}/o?uploadType=media&name={object_name}"
+            url = f"https://storage.googleapis.com/upload/storage/v1/b/{bucket_name}/o?uploadType=media&name={quote(object_name, safe='')}"
             data = json.dumps(value)
             self.sync_client.post(url=url, data=data, headers=headers)
         except Exception as e:
@@ -59,7 +60,7 @@ async def async_set_cache(self, key, value, **kwargs):
             headers = self._construct_headers()
             object_name = self.key_prefix + key
             bucket_name = self.bucket_name
-            url = f"https://storage.googleapis.com/upload/storage/v1/b/{bucket_name}/o?uploadType=media&name={object_name}"
+            url = f"https://storage.googleapis.com/upload/storage/v1/b/{bucket_name}/o?uploadType=media&name={quote(object_name, safe='')}"
             data = json.dumps(value)
             await self.async_client.post(url=url, data=data, headers=headers)
         except Exception as e:
@@ -72,7 +73,7 @@ def get_cache(self, key, **kwargs):
             headers = self._construct_headers()
             object_name = self.key_prefix + key
             bucket_name = self.bucket_name
-            url = f"https://storage.googleapis.com/storage/v1/b/{bucket_name}/o/{object_name}?alt=media"
+            url = f"https://storage.googleapis.com/storage/v1/b/{bucket_name}/o/{quote(object_name, safe='')}?alt=media"
             response = self.sync_client.get(url=url, headers=headers)
             if response.status_code == 200:
                 cached_response = json.loads(response.text)
@@ -91,7 +92,7 @@ async def async_get_cache(self, key, **kwargs):
             headers = self._construct_headers()
             object_name = self.key_prefix + key
             bucket_name = self.bucket_name
-            url = f"https://storage.googleapis.com/storage/v1/b/{bucket_name}/o/{object_name}?alt=media"
+            url = f"https://storage.googleapis.com/storage/v1/b/{bucket_name}/o/{quote(object_name, safe='')}?alt=media"
             response = await self.async_client.get(url=url, headers=headers)
             if response.status_code == 200:
                 return json.loads(response.text)
diff --git a/tests/test_litellm/caching/test_gcs_cache.py b/tests/test_litellm/caching/test_gcs_cache.py
index e77524db98ca..40bfa447d638 100644
--- a/tests/test_litellm/caching/test_gcs_cache.py
+++ b/tests/test_litellm/caching/test_gcs_cache.py
@@ -44,3 +44,64 @@ async def test_gcs_cache_async_set_and_get(mock_gcs_dependencies):
     mock_gcs_dependencies["async_client"].get.return_value.text = '{"foo": "bar"}'
     result = await cache.async_get_cache("key")
     assert result == {"foo": "bar"}
+
+
+@pytest.mark.asyncio
+async def test_gcs_cache_async_get_encodes_object_name_in_path(mock_gcs_dependencies):
+    """
+    Regression test for https://github.com/BerriAI/litellm/issues/30377
+
+    When gcs_path is set, the object name contains a '/' (e.g. "my_cache/<hash>").
+    The GCS JSON API requires the object name in the GET path to be URL-encoded,
+    so the '/' must be sent as '%2F'. Otherwise GCS returns 404 and every read
+    silently misses.
+    """
+    cache = GCSCache(bucket_name="test-bucket", gcs_path="my_cache/")
+
+    mock_gcs_dependencies["async_client"].get.return_value.status_code = 200
+    mock_gcs_dependencies["async_client"].get.return_value.text = '{"foo": "bar"}'
+
+    result = await cache.async_get_cache("abc123")
+    assert result == {"foo": "bar"}
+
+    called_url = mock_gcs_dependencies["async_client"].get.call_args.kwargs["url"]
+    # The slash from gcs_path must be percent-encoded in the path segment.
+    assert "/o/my_cache%2Fabc123?alt=media" in called_url
+    assert "/o/my_cache/abc123" not in called_url
+
+
+def test_gcs_cache_get_encodes_object_name_in_path(mock_gcs_dependencies):
+    """Sync counterpart of the regression test for issue #30377."""
+    cache = GCSCache(bucket_name="test-bucket", gcs_path="my_cache/")
+
+    mock_gcs_dependencies["sync_client"].get.return_value.status_code = 200
+    mock_gcs_dependencies["sync_client"].get.return_value.text = '{"foo": "bar"}'
+
+    result = cache.get_cache("abc123")
+    assert result == {"foo": "bar"}
+
+    called_url = mock_gcs_dependencies["sync_client"].get.call_args.kwargs["url"]
+    assert "/o/my_cache%2Fabc123?alt=media" in called_url
+    assert "/o/my_cache/abc123" not in called_url
+
+
+def test_gcs_cache_set_encodes_object_name_in_query(mock_gcs_dependencies):
+    """
+    The set path uses the object name as a query parameter. Encoding it keeps
+    both sides symmetric so the key written matches the key read back.
+    """
+    cache = GCSCache(bucket_name="test-bucket", gcs_path="my_cache/")
+    cache.set_cache("abc123", {"foo": "bar"})
+
+    called_url = mock_gcs_dependencies["sync_client"].post.call_args.kwargs["url"]
+    assert "name=my_cache%2Fabc123" in called_url
+
+
+@pytest.mark.asyncio
+async def test_gcs_cache_async_set_encodes_object_name_in_query(mock_gcs_dependencies):
+    """Async counterpart of test_gcs_cache_set_encodes_object_name_in_query."""
+    cache = GCSCache(bucket_name="test-bucket", gcs_path="my_cache/")
+    await cache.async_set_cache("abc123", {"foo": "bar"})
+
+    called_url = mock_gcs_dependencies["async_client"].post.call_args.kwargs["url"]
+    assert "name=my_cache%2Fabc123" in called_url