The Third Alibi is a 1961 British 'B'[1] thriller film directed by Montgomery Tully and starring Laurence Payne, Patricia Dainton, Jane Griffiths and Edward Underdown.

Cleo Laine (billed as a guest star) is seen singing a musical number during a brief sequence set in a theatre; her piano accompanist is an uncredited (and unspeaking, though clearly visible) Dudley Moore, in his first film role.

The Monthly Film Bulletin wrote: "Despite one or two flaws in the story, this is a cleverly worked out little thriller whose theatrical development and powerful twist ending ensure continuity of excitement.

Compact, low-key, but exciting ... this later work is, characteristically, constructed with precision; and moves smoothly and swiftly towards an effective and ingenious denouement.

Blame playwrights Pip and Jane Baker for the elaborate murder games, but even they are betrayed by a cast incapable of holding its own in an amateur theatrical.