Named after Westbourne, a medieval hamlet around Westbourne Green.
Westbourne was recorded as Westeburn in 1222. Most accounts take the name from the long-buried River Westbourne, the 'western stream'; the Victoria County History thinks it began as the place on the west side of the stream, which later came to be called after it. A large house on the green, rebuilt in the 1740s as Westbourne Place, was later called Westbourne Park.