Westby-with-Plumptons is a civil parish in Lancashire, England. The parish is in Fylde district and contains the hamlets of Great Plumpton, Little Plumpton, Lower Ballam, Higher Ballam, Moss Side, Peel, and Westby. At the 2011 census, the parish had a population of 1,205. Westby and Plumpton are mentioned in the Domesday Book, as "Westbi" and "Pluntun".