Former Bradford City, Chelsea and Brentford star lands coaching role with Championship outfit
The 50-year-old has left his post as Chelsea’s loan player technical coach to take up the new role with the Lions.
He will be assisting the club’s new head coach, his former Blues colleague Joe Edwards.
Both have been drafted in following Millwall’s decision to part ways with Gary Rowett.
Millwall’s chairman James Berylson told the club’s official website: "We welcome both Joe and Andy to The Den with open arms and look forward to seeing the impact they can make on and off the pitch throughout what we hope to be a long relationship with Millwall."
Myers made a total of 97 appearances in all competitions for Bradford, representing the club between 1999 and 2003.
His move to Millwall has been made on the same day as a change in the dugout at Valley Parade.