Sam Bornstein (1920 - 1990) was a British Trotskyist historian and activist.
Bornstein was a member of the ILP Guild of Youth, but eventually moved towards Trotskyist ideas and joined the Workers International League, helping to build their branch in Stepney.
With Al Richardson, published three books on the history of Trotskyism in Britain through their "Socialist Platform" publishing house. In 1988 they founded the journal Revolutionary History, dedicated to the history of the anti-Stalinist left.