diff --git a/litellm/integrations/s3_v2.py b/litellm/integrations/s3_v2.py
index 405bf9698cc..91955655118 100644
--- a/litellm/integrations/s3_v2.py
+++ b/litellm/integrations/s3_v2.py
@@ -7,6 +7,7 @@ NOTE 1: S3 does not provide a BATCH PUT API endpoint, so we create tasks to uplo
 """
 
 import asyncio
+import re
 from datetime import datetime
 from typing import List, Optional, cast
 
@@ -472,8 +473,10 @@ class S3Logger(CustomBatchLogger, BaseAWSLLM):
             if user_api_key_alias:
                 prefix_components.append(user_api_key_alias)
 
-        # Construct full prefix path
+        # Construct full prefix path (sanitize characters invalid in S3 keys)
         prefix_path = "/".join(prefix_components)
+        # Replace spaces and other problematic characters to prevent S3 signing errors
+        prefix_path = re.sub(r"[\s]+", "_", prefix_path)
         if prefix_path:
             prefix_path += "/"
 
diff --git a/tests/logging_callback_tests/test_s3_space_sanitize.py b/tests/logging_callback_tests/test_s3_space_sanitize.py
new file mode 100644
index 00000000000..a98bb253841
--- /dev/null
+++ b/tests/logging_callback_tests/test_s3_space_sanitize.py
@@ -0,0 +1,44 @@
+"""
+Test that S3 prefix path sanitizes spaces in team_alias and key_alias.
+
+Fixes: https://github.com/BerriAI/litellm/issues/25019
+"""
+
+import re
+
+
+def _sanitize_prefix(prefix_path: str) -> str:
+    """Mirror the sanitization logic from s3_v2.py"""
+    return re.sub(r"[\s]+", "_", prefix_path)
+
+
+def test_team_alias_with_spaces_sanitized():
+    """Team names with spaces should have spaces replaced by underscores."""
+    prefix_components = ["Cloud Tooling", "ugie-dev"]
+    prefix_path = "/".join(prefix_components)
+    prefix_path = _sanitize_prefix(prefix_path)
+    assert prefix_path == "Cloud_Tooling/ugie-dev"
+
+
+def test_team_alias_with_multiple_spaces():
+    """Multiple consecutive spaces collapse to a single underscore."""
+    prefix_components = ["My  Great   Team"]
+    prefix_path = "/".join(prefix_components)
+    prefix_path = _sanitize_prefix(prefix_path)
+    assert prefix_path == "My_Great_Team"
+
+
+def test_team_alias_no_spaces_unchanged():
+    """Team names without spaces pass through unchanged."""
+    prefix_components = ["engineering", "prod-key"]
+    prefix_path = "/".join(prefix_components)
+    prefix_path = _sanitize_prefix(prefix_path)
+    assert prefix_path == "engineering/prod-key"
+
+
+def test_team_alias_with_tabs_and_newlines():
+    """Tabs and newlines are also replaced."""
+    prefix_components = ["team\twith\ttabs"]
+    prefix_path = "/".join(prefix_components)
+    prefix_path = _sanitize_prefix(prefix_path)
+    assert prefix_path == "team_with_tabs"