Socialist Action may refer to one of several socialist (mostly Trotskyist) political groups in several countries.
In alphabetical order (after country):
Socialist Action Group (Australia) was a breakaway group from the Trotskyist Socialist Alternative (Australia). It had no formal international affiliation, but had its roots in groups aligned with the International Socialist Tendency. In February 2008, it joined with the International Socialist Organisation and ISO splinter-group Solidarity to form a new group called Solidarity, representing the IST in Australia.
Socialist Action (UK) (also known as Socialist Action Group (UK)) is a small Trotskyist group in the United Kingdom that published a magazine of the same name until 2001. It is a former section of the reunified Fourth International.