Stephen Thomas Dartnell (died 1994) was a British actor, who appeared in several television programmes. He is best known for his two 1964 appearances in the first season of Doctor Who. He portrayed Yartek, leader of the Voord, in The Keys of Marinus and John, a mineralogist who has been driven to mania, in The Sensorites. Dartnell also made appearances in the 1960 feature films Circle of Deception and Oscar Wilde. He was also a theatre director and was active with the Citizens Theatre in Glasgow.