Socialist Workers' Party (Finnish: Sosialistinen Työväenpuolue, Swedish: Socialistiska Arbetarepartiet) was a political party in Finland. The STP was founded in 1973 as split from Social Democratic Union of Workers and Smallholders (TPSL). STP emerged from a group that did not approve of the return of TPSL to the Social Democratic Party. In February 1990, STP chairman Pentti Waltzer said the party would join the new Left Alliance if Democratic Alternative decided to merge with it, which later happened.