diff --git a/src/axolotl/cli/main.py b/src/axolotl/cli/main.py
index de8bff9ca..e8dbf9f12 100644
--- a/src/axolotl/cli/main.py
+++ b/src/axolotl/cli/main.py
@@ -209,7 +209,7 @@ def train(
                         accelerate_args.append(str(main_process_port))
                     if "num_processes" in kwargs:
                         num_processes = kwargs.pop("num_processes", None)
-                        accelerate_args.append("--num-processes")
+                        accelerate_args.append("--num_processes")
                         accelerate_args.append(str(num_processes))
 
                     base_cmd = ["accelerate", "launch"]