The appointment marks the first major coaching role for the Chelsea legend following his retirement from the professional game last year.
Morris played alongside Lampard at Chelsea, as well as for the England Under-21s, and now he has come along for the ride at Pride Park.
"The team around you is hugely important. It's not just about me as the manager; everyone will have a part to play on the staff and Jody is the first part of that. I am delighted to have him on board," Lampard told Derby's official website.
"Jody has been hugely successful with Chelsea's youth team and he has won everything there is to win in the last few years. He is great at developing young players and that is something we are really going to look to do here.
"Jody played the game at the highest level himself, has a tremendous work ethic and is great in the dressing room. I have known him for so long now and his qualities and personality will bring so much to this club."
Morris's most recent job was in charge of Chelsea's Under-18s.