diff --git a/litellm/llms/anthropic/chat/transformation.py b/litellm/llms/anthropic/chat/transformation.py
index 558c11d8420..855d0a2fdfd 100644
--- a/litellm/llms/anthropic/chat/transformation.py
+++ b/litellm/llms/anthropic/chat/transformation.py
@@ -991,7 +991,6 @@ class AnthropicConfig(AnthropicModelInfo, BaseConfig):
                     for substring in {
                         "haiku-4-5",
                         "haiku-4.5",
-                        "haiku_4_5",
                         "sonnet-4.5",
                         "sonnet-4-5",
                         "opus-4.1",