The Siddeley Tiger was an unsuccessful British aero engine developed shortly after the end of World War I by Siddeley-Deasy.

Developed using two modified cylinder banks from the Siddeley Puma, the Tiger was a liquid-cooled 60-degree V12 engine with the advanced feature of an electric starter motor protected by a friction clutch.

The only aircraft in which the Siddeley Tiger flew was the ill-fated prototype of the twin-engined Siddeley-Deasy Siniai of which three were planned to be produced.

Major problems with both the engines and this experimental bomber aircraft led to cancellation of the projects.

[2] The Siddeley Tiger marked the end of the aero engine line started by Beardmore and Siddeley-Deasy.