Robert Lawrence Leonard (born February 28, 1969), known as Robert Sean Leonard, is an American actor. He is best known for his portrayal of Neil Perry in the drama film Dead Poets Society (1989) and Dr. James Wilson in the medical drama series House (2004–2012).

A prolific stage actor, Leonard won a Tony Award for Best Featured Actor in a Play for his performance in The Invention of Love in 2001. His other theater credits include Candida, Long Day's Journey Into Night, Breaking the Code, The Speed of Darkness, Philadelphia, Here I Come!, Arcadia, The Music Man, Born Yesterday, Fifth of July, and To Kill a Mockingbird.