Revolutionära Socialistiska Partiet (Revolutionary Socialist Party), a Swedish political party founded in 1950. RSP was the first Swedish section of the Fourth International. The party leader was Evald Höglund. The group gathered around a dozen persons. It was active in the 1950 municipal elections in Stockholm (they got 1900 votes) and during the dockers' strike of 1951. RSP published two issues of Internationalen.

RSP was a short-lived party. Soon the leadership of FI ordered RSP to enter SAP and pratice fraction politics, entryism, within this party. The members of RSP opposed this, and the organization was dissolved.