Plantagenet was an electoral district of the Legislative Assembly in Western Australia from 1890 to 1904.

The district, located in the Great Southern area of the state, was one of the original 30 seats contested at the 1890 election.

In 1900, the seat included a number of towns along the Great Southern Railway, including Broomehill, Tambellup, Cranbrook, Tenterden, Kendenup, and Mount Barker, as well as Kojonup, Denmark, and Jerramungup.

[1] Plantagenet existed for four terms of parliament, electing the same member, Albert Hassell, on each occasion.

This Western Australian government-related article is a stub.