The Reformed Political Party (Dutch: Staatkundig Gereformeerde Partij, SGP) is an orthodox Protestant Calvinist political party in the Netherlands. The term Reformed is not a reference to political reform, but is a synonym for Calvinism. The SGP is the oldest political party in the Netherlands in its current form, and has for its entire existence been in opposition. The party has, owing to its orthodox political ideals and its refusal to cooperate in any cabinet, been called a testimonial party.