Megson guided the club to their first ever promotion to the Premier League during a managerial spell at the club and will now fill the gap left by Dave Kemp's retirement.
The 58-year-old has been out of work since leaving Sheffield Wednesday in 2012 but Tony Pulic is delighted to have him on board.
“I’ve known Gary from my early days at Bristol Rovers when his dad Don gave me my debut and Gary would turn up to train as a 17-year-old,” said Pulis.
“He’s been out of things for a while but that’s what attracted me in many ways – he’s fresh, he will hit the ground running and he’s a person I know I can bounce things off."
Megson was equally happy with the appointment and said that he and Pulis share a common footballing philosophy.
“I’m really pleased. I’ve known Tony a long time and although we’ve never lived in each other’s pockets we have similar views on how football should be played and how footballers should behave," he explained.
“I loved my time here although it’s a long time ago now. You obviously have the club you grow up supporting which you always consider to be your club. But this is as close to that relationship as possible – and I can’t pay it a higher compliment then that. It’s a terrific club with terrific support.”
Welcome back to the Baggies, Gary Megson!#WBA https://t.co/jFSEKwoL1O
— West Bromwich Albion (@WBA) 28 de julio de 2017
"I loved my time here... It's a terrific club with terrific support."#WBA pic.twitter.com/o2Tj6YAZYT
— West Bromwich Albion (@WBA) 28 de julio de 2017