The Boulton Paul P.111 is an experimental aircraft designed and produced by the British aircraft manufacturer Boulton Paul. It was amongst the first aircraft designed to explore the characteristics of the tailless delta wing configuration.

Boulton Paul Aircraft Ltd was a British aircraft manufacturer that was incorporated in 1934, although its origins in aircraft manufacturing began earlier in 1914 and lasted until 1961. The company mainly built and modified aircraft under contract to other manufacturers, but had a few notable designs of its own, such as the Defiant fighter and the Balliol trainer.