A belt clamp with a pivotal article carrier attached thereto includes a base and a cover hinged together at the top. The cover includes a passageway at the lower end to accept a barb-like fastener integral with lower end of base to lock clamp closed. A tongue projects inwardly from the cover to contact and inhibit movement of a duty belt inside the clamp. The base includes a pair of intersecting arcuate slots and a reversible insert having one arcuate slot to make the clamp usable by either right- or left-handed users. A movable belt width adjustment bar is mounted inside the clamp to accommodate belts of various widths. Bosses around the lower opening of the cover inhibit twisting of locked clamp to prevent inadvertent opening. A locking plate is provided to inhibit rotation of fasteners used in pivotal mounting of an article carrier to the belt clamp.