Calne /ˈkɑːn/ is a town and civil parish in Wiltshire, southwestern England, at the northwestern extremity of the North Wessex Downs hill range, a designated Area of Outstanding Natural Beauty.

Calne is on a small river, the Marden, that rises 2 miles (3 kilometres) away in the Wessex Downs, and is the only town on that river. It is on the A4 road national route 19 mi (31 km) east of Bath, 6 mi (10 km) east of Chippenham, 13 mi (21 km) west of Marlborough and 16 mi (26 km) southwest of Swindon. Wiltshire's county town of Trowbridge is 15 mi (24 km) to the southwest, with London 82 mi (132 km) due east as the crow flies. At the 2011 Census, Calne had 17,274 inhabitants.