Willem Inte Onsman (Harlingen, 28 September 1872 - Amsterdam, 26 August 1929) was a Dutch playwright and trade unionist.
Born in the province of Friesland, Inte Onsman moved to Amsterdam after the death of his father.
As a young man he joined a theatre company as an actor, but a few years later he left the group and started his own barbershop.
His socialist sympathies drew him to the Dutch social-democratic party SDAP and the barbers trade union.
His most successful was Het licht in den nacht (A light in the night) which dealt with the poor during World War I.