The first-team coach has left the club after six months.
Williams had recently been working as the interim boss for the club after the departure of Dougie Freedman.
He took charge of the final 10 matches of the campaign after originally being appointed as first-team assistant coach in December last year.
His departure will not come as a surprise to many Forest fans. He was brought in by Dougie Freedman and with him gone, this seemed a likely development once the season ended.
With the impending takeover from Greek businessman and Olympiakos owner Evangelos Marinakis getting ever closer, as reported once again by Greek site SDNA today, Forest are set to appoint a new manager in the coming weeks and Williams might well have found himself gone after that.
Williams took charge of 10 games for the club, guiding them to safety after losing four of his first five games in charge.
Most fans seemed to wish him well on his departure but he had only been at the club for six months, so nobody seemed too upset to see him go.
Here is how Nottingham Forest fans reacted on Twitter…
Tarrah Paul Williams. Thanks for minding the office & the 5 game unbeaten run at the end... #NFFC— Growler (@khakipillowslip) May 12, 2016
Shame about Williams but no real surprise. Seemed a popular coach but things did seem to improve when Gary Brazil got more involved #NFFC— Dave Holmes (@DaveHolmes1) May 12, 2016
Williams did nothing in the dugout. Brazil made the calls and instructed players... Williams was just the puppet who followed his lead #NFFC— Dan (@Dan_LowerBC) May 12, 2016
Good luck to Paul Williams wherever he end's up next,always looked like he was about to burst into tears whenever I saw him interviewed#Nffc— Andrew stafford (@Nffcstaff) May 12, 2016
Thanks for all your efforts Paul Williams, hopefully this means we've got someone lined up but it's forest we're talking about #nffc— Tom (@TomNffc4) May 12, 2016
Surely Williams leaving suggests an appointment is imminent. #nffc— Warren Allsworth (@warrenallsworth) May 12, 2016
Wasn't Williams due to leave & go to the FA anyway? #nffc— Dave Garner (@Dave_Garner68) May 12, 2016
Paul Williams leaving Nottingham Forest is hardly surprising. #nffc— Matt Lynch (@mattlyynch) May 12, 2016
Unless of course the new manager is decided and has told #nffc he doesn't want Williams?— YouAreMyForest (@YouAreMyForest) May 12, 2016
Decent bloke Paul Williams seemed, wish him well for the future #nffc— Gaz Brown (@Gaz23Brown) May 12, 2016
Seems a bit harsh on Williams. Could have just kept him & at least given the new manager the choice of keeping him on as a coach. #nffc— YouAreMyForest (@YouAreMyForest) May 12, 2016