The 2015 Senior Open Championship was a senior major golf championship and the 29th Senior Open Championship, held on 22–25 July at Sunningdale Golf Club in Sunningdale, England. It was the second Senior Open Championship played at the course and the 13th Senior Open Championship played as a senior major championship. Marco Dawson won by one stroke over Bernhard Langer. It was Dawson's first senior major championship victory.