William Wallis (20 November 1936 – 6 September 2013) was an English actor who appeared in numerous radio[3] and television roles,[4][5][6] as well as in the theatre.

(1993) Wallis played the disgruntled scientist who kills his boss in Poirot (The Underdog).One longstanding role was that of the hard-drinking Nick McKenzie in the BBC drama Dangerfield, from 1995 until 1998.

Some of Wallis's most frequent appearances were on BBC Radio 4 for The Afternoon Play and the Classic Serial, but he was also in the cast of the long-running sketch show Week Ending, and in the first episode of The Hitchhiker's Guide to the Galaxy in 1978, originating the roles of Mr. Prosser and Prostetnic Vogon Jeltz.

He also featured as the third party in the "...is approached by Ivor Cutler" series of short humorous pieces, including playing the Miner, the Farmer and the Sheet Metal Worker.

Wallis's film appearances include The Bed Sitting Room (1969), The Romantic Englishwoman (1975), The Orchard End Murder (1981), Brazil (1985), The Whistle Blower (1986), The Great Escape II: The Untold Story (1988), The Fool (1990), Splitting Heirs (1993), Keep the Aspidistra Flying (1997) and The Other Boleyn Girl (2008).