Abstract: A guard for covering a wheel pulley of a powered sickle-bar mower. The inventive device includes a semi-circular panel positionable over the wheel pulley of the mower. A pair of lateral panels extend from opposed ends of the semi-circular panel and cooperate with a pair of mounting projections to secure the semi-circular panel to a pulley housing of the mower. The device cooperates with a cover plate of the mower to fully enclose the wheel pulley to preclude an entrance of debris into the pulley housing which could jam the wheel pulley.