diff --git a/evoprompt/models.py b/evoprompt/models.py
index 4e7b36116239317d849d77b5ae8202ea137447f6..a2e3d8c95aec4237885d2338d8b5f3b604b016c3 100644
--- a/evoprompt/models.py
+++ b/evoprompt/models.py
@@ -133,7 +133,9 @@ class LLMModel(ABC):
             sort_keys=True,
         )
         cache_key = (
-            str(self.model_name) + '/' + hashlib.sha1(unique_options_key.encode()).hexdigest()
+            str(self.model_name).replace("/", "_")
+            + "/"
+            + hashlib.sha1(unique_options_key.encode()).hexdigest()
         )
         return cache_key