A safety device for a motorcycle gear lever includes a gear lever and a mounting member. The gear lever has a base member, a pivoting member mounted pivotally on the base member and a foot post. The foot post is mounted on the pivoting member and has an annular groove. The mounting member is disposed adjacent to the gear lever and has a mounting hole and a key lock having a locking member. When the pivoting member pivots, the foot post is mounted in the mounting hole and the locking member of the lock selectively engages the annular groove of the foot post to lock the foot post.