Roman Catholic State Party (Dutch: Roomsch-Katholieke Staatspartij, RSKP) was a Dutch Catholic Christian democratic political party. The party was founded in 1926 as a continuation of the General League of Roman Catholic Caucuses. In 1945 the party became the Catholic People's Party (KVP).
The RKSP was founded 3 June 1926, as the continuation of the General League of Roman Catholic Caucuses. Since 1918, the General League called itself RKSP informally. Instead of the loose league of caucuses with little party discipline, as the General League was, the RKSP became a real party, with stronger party discipline and organisation. In 1922 another Catholic party, the Roman Catholic People's Party, was founded by former members of the General League. It was oriented towards Catholic workers. The General League received little competition from this party, but accelerated the RKSP's process of party-formation.
During the 1920s and the 1930s, the RKSP was the biggest party in the Netherlands, receiving a steady 30% percent of the vote at each election. During this entire period the party was in government, in coalition with the Anti-Revolutionary Party (ARP) and the Christian Historical Union (CHU), two Protestant parties. This coalition was called the Coalition. Despite its success, the party was blocked from many political offices. Positions like the Vice-President of the Council of State and the President of the Senate and House of Representatives of the States General were all occupied by Protestants. The RKSP also supplied only one Prime Minister, Charles Ruijs de Beerenbrouck, between 1929 and 1933.