The Socialist Equality Party (SEP) is an American Trotskyist political party. SEP first formed in 1964 as the American Committee for the Fourth International, created by expelled members of the Socialist Workers Party. SEP and its previous forms were associated with the International Committee of the Fourth International (ICFI), a Trotskyist political international.

SEP describes itself as a revolutionary socialist party, because the SEP believes capitalism is "beyond reform" and only "a revolutionary movement that has as its aim the establishment of workers' power" can win socialism.

Notable members include David North, Jerry White, and Joseph Kishore.

In the 1950s, most Trotskyists in the United States were members of the Socialist Workers Party (SWP), which was part of the Fourth International's (FI) tendency International Committee of the Fourth International (ICFI).

In 1958, SWP adopted a policy of "regroupment": Pursuit of former members of Stalinist communist parties, who had been disillusioned by the Secret Speech.

In 1961, Tim Wohlforth, James Robertson, and other SWP members who opposed regroupment created a tendency within the SWP, the Revolutionary Tendency (RT). RT saw the SWP as shifting toward the FI's other tendency, the International Secretariat of the Fourth International (ISFI), led by Michel Pablo. RT opposed "Pabloite" politics and Pablo's "entryism sui generis" plan, in which Trotskyists would maintain separate parties but personally enter into communist and social democratic parties. RT developed links with the Socialist Labour League in Britain, led by Gerry Healy. Lyndon LaRouche was briefly an RT member.

In 1962, the RT split: Robertson's majority kept the name. Wohlforth's minority renamed itself the Reorganized Minority Tendency (RMT).

In 1963, in preparation for merging the ICFI with the ISFI, Wohlforth was removed from the SWP's Political Committee.