Former Leeds, Everton, Newcastle, Bolton and Sheffield United midfielder Speed was found dead at his Cheshire home at the age of 42, provoking an outpouring of grief for a man liked and respected throughout the football community.
Staff at the Football Association of Wales, including current Wales boss Chris Coleman, met to remember Speed at the governing body's headquarters in Cardiff. Flowers were laid while an image of Speed outside the building was lit up.
Several members of the Wales set-up paid tribute on Twitter to the man who had guided his country to four wins from his last five games in charge.
Wales captain Ashley Williams tweeted: "RIP Gary Speed", and several of his team-mats also left messages on the social media site. Tottenham star Gareth Bale, posted: "Remembering Gary Speed 1 year on #RIP", while Celtic midfielder Joe Ledley tweeted: "A year ago today a legend left us, but will never be forgotten. Rip Gary speed."
Striker Robert Earnshaw, who played alongside Speed for Wales, said: "Remembering #GarySpeed today.R.I.P. I learnt alot from him."
John Hartson, another of Speed's former team-mates, now part of Coleman's backroom staff, tweeted: "It's one year today since we lost a wonderful man. My thoughts today are with his family.. God bless."
There was also a message from Sepp Blatter. A post on the FIFA president's official Twitter site read: "Thoughts with Gary Speed's family 1 year on from his passing. Sadly missed by the game he served with such distinction".
All of Speed's former clubs posted messages in his memory and there was a minute's applause at Elland Road, where Speed began his career and won the 1992 league title, ahead of Leeds' Championship fixture against Leicester.
Former Wales midfielder Matt Jones also completed a 24-hour cycle in memory of Speed. The 32-year-old had already taken part in a series of half-marathons, the London marathon, a run up and down Mount Snowdon, and a sky-dive, raising thousands of pounds for charities supported by Speed, including the Bobby Robson Foundation, the John Hartson Foundation and the Spinal Injuries Association.