The Sagtikos State Parkway, also known as the Sagtikos or Sagtikos Parkway, is a north–south limited-access parkway in Suffolk County on Long Island, New York, in the United States. It begins at an interchange with the Southern and Heckscher state parkways in the hamlet of West Islip and goes north to a large cloverleaf interchange with the Northern State Parkway in the town of Smithtown, where the Sagtikos ends and the road becomes the Sunken Meadow State Parkway. The parkway comprises the southern half of New York State Route 908K (NY 908K), an unsigned reference route, with the Sunken Meadow State Parkway forming the northern portion. Commercial vehicles are prohibited from using the Sagtikos State Parkway, a restriction that applies to most parkways in the state.