John Sandeman Allen (30 May 1892 – 29 September 1949) was a British Conservative Party politician. He was a Member of Parliament (MP) for Birkenhead West from 1931 to 1945. At the 1945 general election he stood in the previously Conservative-held South Norfolk constituency, but the Labour candidate, Christopher Mayhew, was elected as the constituency's MP.

• Craig, F. W. S. (1983) [1969]. British parliamentary election results 1918–1949 (3rd ed.). Chichester: Parliamentary Research Services. ISBN 0-900178-06-X.
• Leigh Rayment's Peerage Pages ^{[self-published source] [better source needed]}

• Hansard 1803–2005: contributions in Parliament by John Sandeman Allen