Kenneth Lonergan (born October 16, 1962) is an American playwright, screenwriter and film director. He is known for his works, which explore complex emotional and interpersonal dynamics.

He has received several awards, including an Academy Award and a BAFTA Award, as well as nominations for three Golden Globe Awards, a Pulitzer Prize, a Laurence Olivier Award, and three Tony Awards. In 1982, Lonergan wrote his first one-act play, The Rennings Children. He then earned acclaim for a string of off-Broadway plays, including This is Our Youth (1996), The Waverly Gallery (2000), and Lobby Hero (2001), which were later revived on Broadway, earning him nominations for three Tony Awards for Best Revival of a Play in 2015, 2019, and 2018, respectively.