The 57-year-old recently left his role on the backroom staff at Championship side Cardiff City after five years in Wales, returning to the club he played over 50 times for during his playing career in 2017.
He joins up with another former Hatter, Graham Alexander, who was named in charge at Fir Park back in January 2021.
Dibble moved to Kenilworth Road in 1984 for £125,000, producing a starring role in the Littlewoods Cup Final victory over Arsenal at Wembley in 1988, saving Nigel Winterburn’s penalty in the second half as the Hatters went on to triumph 3-2.
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He played 39 times in two spells at Luton, and on his move north of the border, Dibble, who turned out for Aberdeen and Rangers in his career, told the Motherwell official website: “It is exciting to join up with Graham and the rest of the coaching staff.
“I am looking forward to the season ahead and getting to know everyone.”
Alexander, who made 183 appearances, scoring 17 goals for the Hatters between 1995-99 added: “I’m delighted to welcome Andy to the club as head of goalkeeping.
“He has vast knowledge as a coach and his top level experience from his playing days will certainly help our keepers.
"Having experienced the Scottish game before, I know how excited he is to join us and help us keep progressing.”