A cam-actuated locking system for the inboard barrier of a wheelchair lift is provided. The lift includes a linkage system having a push arm and a slide block. The push arm includes a sliding member with a first keyhole, and a fixed member with a second keyhole. A lock mechanism is pivotally coupled to the sliding member, and includes a keyhole insert. The second keyhole of the fixed member cooperates with the first keyhole and the lock mechanism so that when the keyhole insert of the lock mechanism inserts into the aligned keyholes of the fixed and sliding members, the inboard barrier is locked in a barrier position.