Motor Sundaram Pillai is a 1966 Indian Tamil-language drama film directed by S. S. Balan and written by Veppathur Kittoo. A remake of the Hindi film Grahasti (1963), itself based on the American film The Remarkable Mr. Pennypacker (1959), the film stars Sivaji Ganesan, Ravichandran, Sowcar Janaki and Jayalalithaa. It revolves around a man who leads a double life, having two sets of families.

Motor Sundaram Pillai is the directorial debut of Balan, whose father Vasan produced the film under Gemini Studios. After Kittoo completed the screenplay, Ganesan was approached to star but declined; Vasan then produced Kittu's screenplay as Grahasti. When Ganesan saw this film, he offered to act if Kittu made a Tamil version, and was cast.

Motor Sundaram Pillai was released on 26 January 1966. The film was commercially successful, running for over 100 days in theatres.