Stuart Bruce Greenwood (born August 12, 1956) is a Canadian actor and producer. He is known for his role as the American president John F. Kennedy in Thirteen Days, for which he won the Satellite Award for Best Supporting Actor – Motion Picture, and as Captain Christopher Pike in J.J. Abrams's Star Trek movie reboot series. He has been nominated for three Canadian Screen Awards, once for Best Actor (for Elephant Song) and twice for Best Supporting Actor (for The Sweet Hereafter and Being Julia).

He is known for his roles as Nick Parsons in Double Jeopardy, Stuart Ramsey in Passenger 57, Bob Andrews in Father's Day, Earl Cavanaugh in Here on Earth, National Security Advisor Bill Sokal in Rules of Engagement, JFK in Thirteen Days, Anthony 'Tony' Leighton in Swept Away, Cmdr. Robert Iverson in The Core; Lt. Bennie Macko in Hollywood Homicide, Lawrence Robertson in I, Robot, Lord Charles in Being Julia, Nolan Walsh in Racing Stripes, Jack Dunphy (Truman Capote's lover) in Capote; Hugh Sullivan in The Mermaid Chair, Professor Davis McClaren in Eight Below, Jack McCready in Deja Vu, Keenan Jones / Garrett in I'm Not There, the President in National Treasure: Book of Secrets, Christopher Pike in Star Trek and its sequel Star Trek Into Darkness, George McCray in A Dog Named Christmas, Lance Fender in Dinner for Schmucks, Stephen Meek in Meek's Cutoff, Cooper in Super 8, Bill Kill Cullen in The Place Beyond the Pines, Charlie Anderson in Flight, Hugh Butterfield in Endless Love, Vince in The Captive, Andrew Heyward in Truth (2015), Dr. Jake Houseman in the TV movie version of Dirty Dancing (2017), Uncle Dean in Kodachrome, the US President in Kingsman: The Golden Circle, Gerald in Gerald's Game, Robert McNamara in The Post, and Dr. John Dalton in Doctor Sleep.

His best known TV roles are as Dr. Randolph Bell on The Resident, Gil Garcetti on American Crime Story, Emmet Cole on The River, Mitch Yost on John from Cincinnati, Dr. Nathan Bradford on Sleepwalkers, Thomas Veil on Nowhere Man, Jack Gage on Legmen, Pierce Lawton on Knot's Landing, and Dr. Seth Griffin on St. Elsewhere.

He has voiced Bruce Wayne / Batman in the animated series Young Justice and in several Batman cartoon videos, and voiced Chiron in the animated series Class Titans.