The 42-year-old, who also played for the Blades, was found dead at his home in Cheshire on the morning of November 27, 2011, prompting an outpouring of grief.
Speed played for Leeds United between 1984 and 1996, where he won the English Football League First Division Championship in 1992. He later played for Everton, Newcastle United and Bolton Wanderers before joining Sheffield United in 2008.
Today, Leeds United tweeted: “RIP Gary Speed, one of our greatest.”
A Facebook post from the club read: “Four years on from his tragic passing, today we remember the great Gary Speed. Never forgotten.”
An inquest recorded a narrative verdict as the coroner could not be certain he had intended to take his own life.
Speed, capped 85 times by Wales, was in charge of the Blades for 18 games from August to December 2010, before being appointed Wales manager.