The Sociaal Democratische Arbeiders Partij (SDAP) was a Dutch political party that existed from 1894 to 1946.

The SDAP was a social democratical party. It was founded in Zwolle in 1894. In 1897 it had two seats in the Second Chamber for the first time; in 1939 it participated in the government for the first time.

Important members were:

• Carel Steven Adama van Scheltema
• Jan Buskes
• Sicco Mansholt
• Pieter Jelles Troelstra co-founder of the SDAP
• Hendrik Spiekman co-founder of the SDAP
• Pieter Lodewijk Tak.

Later the parted merged with the Vrijzinnig Democratische Bond en de Christen Democratische Unie (CDU) to form the current social-democratic polical party in the Netherlands, the PvdA.