diff --git a/bilby/core/result.py b/bilby/core/result.py
index 9db583ec6950943c15a7a21aa4aba6b078c32453..bbe55e2d3c3ff6c6d714955cff95d3aafdc88e88 100644
--- a/bilby/core/result.py
+++ b/bilby/core/result.py
@@ -196,6 +196,12 @@ class Result(dict):
         if dictionary.get('priors', False):
             dictionary['priors'] = {key: str(self.priors[key]) for key in self.priors}
 
+        # Convert callable kwargs to strings to avoid pickling issues
+        if hasattr(self, 'kwargs'):
+            for key in self.kwargs:
+                if hasattr(self.kwargs[key], '__call__'):
+                    self.kwargs[key] = str(self.kwargs[key])
+
         try:
             deepdish.io.save(file_name, dictionary)
         except Exception as e: