diff --git a/generate_opcodes_file.py b/generate_opcodes_file.py
index 6d92836..339a36d 100644
--- a/generate_opcodes_file.py
+++ b/generate_opcodes_file.py
@@ -56,8 +56,11 @@ def replace_line_with_new_opcode(line, diff, ver, old_ver):
 @click.option(
     "--reverse", is_flag=True, help="Applies the diff file in the opposite direction"
 )
+@click.option(
+    "-o", "--output", type=click.Path(exists = False, resolve_path=True), help="Output filename"
+)
 def generate_opcodes_file(
-    old_version_string, new_version_string, diff_file, opcodes_file, reverse
+    old_version_string, new_version_string, diff_file, opcodes_file, reverse, output
 ):
     """
     Parses an OPCODES_FILE and applies a JSON DIFF_FILE to generate a new one.
@@ -81,7 +84,10 @@ def generate_opcodes_file(
             )
         )
 
-    new_filename = f"Ipcs.{new_version_string}.h"
+    if output:
+        new_filename = output
+    else:
+        new_filename = f"Ipcs.{new_version_string}.h"
     with open(new_filename, "w+") as f:
         f.writelines(queued_lines)