diff --git a/scripts/lock.py b/scripts/lock.py
index 4b7de691cc..a8071825ae 100644
--- a/scripts/lock.py
+++ b/scripts/lock.py
@@ -158,6 +158,11 @@ def parse_args(argv):
         default=None,
         help='OS (distro) version such as "12.10"',
     )
+    parser.add_argument(
+        '--arch',
+        default=None,
+        help='architecture (x86_64, i386, armv7, arm64)',
+    )
     parser.add_argument(
         '--json-query',
         default=None,
diff --git a/teuthology/lock.py b/teuthology/lock.py
index 34b5331291..d9930a9178 100644
--- a/teuthology/lock.py
+++ b/teuthology/lock.py
@@ -333,7 +333,7 @@ def main(ctx):
                 machines_to_update.append(machine)
     elif ctx.num_to_lock:
         result = lock_many(ctx, ctx.num_to_lock, ctx.machine_type, user,
-                           ctx.desc, ctx.os_type, ctx.os_version)
+                           ctx.desc, ctx.os_type, ctx.os_version, ctx.arch)
         if not result:
             ret = 1
         else: