Tim Matheson (born Timothy Lewis Matthieson; December 31, 1947) is an American actor, director and producer. He is perhaps best known for his portrayal of the smooth-talking Eric 'Otter' Stratton in the 1978 comedy Animal House and has had a variety of other well-known roles, including providing the voice of the lead character in the cartoon TV program Jonny Quest.
At the age of 13, Matheson appeared as Roddy Miller in Robert Young's CBS nostalgia comedy series Window on Main Street during the 1961-1962 television season. In 1964, he provided the voice of the lead character in the cartoon program Jonny Quest. He was also the voice of Jace in the original animated series of Space Ghost. In addition, he played the role of the oldest son, Mike Beardsley, in the film Yours, Mine and Ours, which also starred Lucille Ball and Henry Fonda.
In 1969, he joined the cast of NBC's The Virginian western series in the eighth season, as Jim Horn. He had a guest role in the 14th episode of the second season of Night Gallery, in the story "Logoda’s Heads". In the final season of the television western Bonanza in 1972-1973, Matheson played Griff King, a parolee who tries to reform his life as a worker at the Ponderosa Ranch under Ben Cartwright's watch. He portrayed a young motorcycle cop, Phil Sweet, in the 1973 film Magnum Force. Matheson also appeared earlier in the ABC television comedy series My Three Sons and Leave It to Beaver.