Jan Willem "Willy" Sluiter (Amersfoort, 1873 – The Hague, 1949) was a Dutch painter best known for his views of Dutch villages and their inhabitants, though he also painted portraits of members of high society. His work took part in the art competitions held at four Olympic Games.
The son of a notary, he grew up in Heerenveen and, from 1883, in Zwijndrecht. He studied at the Rotterdam Academy of Visual Arts from 1891 to 1894 and then took lessons at the academy in The Hague. He lived and worked in Dordrecht and Rotterdam, and in coastal villages popular with painters, such as Scheveningen, Katwijk and Laren, where he settled in 1910 before moving to The Hague in 1916. He belonged to several art societies, among them Pictura, Arti et Amicitiae and Pulchri Studio.
His subjects often came from the coast and the lives of fishermen, and he was a sought-after portraitist for the upper classes. He painted the Volendam model Hille Butter several times. Beyond painting, he worked as an illustrator of political cartoons, a poster maker, an advertising freelancer and a book cover designer. Notable are the 38 sheet-music covers he made between 1920 and 1925 for the publisher Scheltens and Giltay, with cabaret texts by the poet Clinge Doorenbos, and his 1926 poster against littering, considered iconic in the Netherlands.
His work has been revisited in exhibitions such as the Dordrechts Museum's 1999 show, marking fifty years since his death, and the Katwijks Museum's 2013–2014 display.