Labour and Socialist International

Labour and Socialist International
Founded	21 May 1923; 101 years ago (21 May 1923)
Dissolved	3 April 1940; 84 years ago (3 April 1940)
Preceded by	Berne International Vienna International
Succeeded by	Socialist International
Ideology	Socialism Labour movement
Political position	Centre-left to left-wing
Colors	Red

The Labour and Socialist International (LSI; German: Sozialistische Arbeiter-Internationale, SAI) was an international organization of socialist and labourist parties, active between 1923 and 1940. The group was established through a merger of the rival Vienna International and the Berne International, and was the forerunner of the present-day Socialist International.

The LSI had a history of rivalry with the Communist International (Comintern), with which it competed over the leadership of the international socialist and labour movement. However, unlike the Comintern, the LSI maintained no direct control over the actions of its sections, being constituted as a federation of autonomous national parties.