Henri Polak (22 February 1868 – 18 February 1943) was a Dutch trade unionist and politician. Polak is best remembered as a longtime president of the General Diamond Workers' Union of the Netherlands (ANDB) and as a founder of the Dutch Social Democratic Workers' Party in 1894. Targeted as a Jew, a marxist, and a trade unionist, Polak was arrested by the Nazis in 1940 but died early in 1943 before he could be deported.