'Thistledown' was a British special forces operation by the 2^nd Special Air Service to cut the rail lines in the area to the north of Rome near Terni and Orvieto in support of 'Shingle', the Allied landings at Anzio in January 1944 (7/8 January 1944).

'Thistledown' was one of the two sub-operations which together with 'Driftwood' constituted 'Maple' (i), and was unsuccessful. Four four-man teams were parachuted into the operational region, but their fate remains unknown.