The 57-year-old managed the Cottagers in 1997-98 and his arrival follows Alan Curbishley's as first-team technical director as Rene Meulensteen strengthens his backroom staff
The former England international, who managed Fulham in the 1997-98 season, will aid head coach Rene Meulensteen and Alan Curbishley at Craven Cottage.
Curbishley was appointed as Fulham's first-team technical director last week and Meulensteen has expressed delight at the subsequent arrival of Wilkins.
"I am delighted that the chairman and the CEO have, again, backed my desire for further experience and support within the backroom staff," said Meulensteen, who took charge of first-team affairs following Martin Jol's departure at the beginning of December.
"Retaining our status of being a Barclays Premier League club next season is vitally important to our long-term plans, and I know that Ray's own experience and his knowledge of the game will be a vital component in our success."
Fulham currently sit 18th in the Premier League, having lost 13 out of 19 games this season, and were beaten 6-0 at Hull City last time out.
Wilkins managed QPR in the top flight prior to his previous stint at Fulham, and has also filled coaching roles with Chelsea, Watford, Millwall and England Under-21s.