Lambert has dismissed suggestions that he was contemplating leaving because his wife still lives in Scotland and insisted that his decision is one based purely on football matters.
"I am bitterly disappointed that we failed to win promotion, but I leave with my head held high," the Scot told Wycombe's official website. "I've enjoyed every minute of my time at Wycombe and I'm proud to have taken the club to a Carling Cup semi-final and to the League Two play-offs.
"This is a great club, but I feel that the time has come for me to move on. I haven't been forced out - the decision to leave is entirely mine - and I don't have another job to go to. I just feel that this is the right thing to do.
"I want to thank the players for their fantastic efforts this season. They're a first-class group of lads who worked incredibly hard for me and never provided a moment's trouble. Whoever takes over will inherit an excellent squad."