Houston and Killellan is a parish, which lies in Renfrewshire Council Area, some 5 miles (9 km) northwest of Paisley in Renfrewshire and 6 miles (10 km) west of Clydebank in West Dunbartonshire.
It is located in the old county of Renfrewshire, which disappeared following the Local Government (Scotland) Act 1974.
The parish has an area of 30.9 sq. km (11.9 sq. miles). Houston and Killellan has Erskine, Kilbarchan and Kilmacolm as its neighbouring parishes.