A pole clamp is disclosed that can firmly attach heavy fixtures to a pole, such as a center or side pole of a special-events tent, with quick and easy fixture mounting and dismounting. The head of a fixture-mounting bolt is downwardly slidable into a T-channel of the clamp, where it rests against a stop pin and rigidly supports the fixture until it is lifted out of the T-channel. A plurality of T-channels can provide for a plurality of fixture attachments at a plurality of orientations. In some embodiments, the clamp includes a pair of identical, hingedly joined, rigid aluminum segments that can be placed on opposite sides of the pole and compressed against the pole by pressing of the unhinged, flanged ends toward each other using a bolt, cam lever, or similar means. The rigid segments can be shaped to accommodate a pole of any cross-sectional size and shape.