The midfielder follows Conor Coady and Matt Doherty in signing news terms, having proved an important part of Nuno Espirito Santo’s squad once again this season.
The Moroccan international, who appeared in last year’s World Cup, is now in his third Molineux campaign, in which time he’s made more than 80 appearances.
The midfielder joined from Angers in 2016 and played an integral role in last season’s promotion to the Premier League, appearing regularly alongside Ruben Neves.
Since promotion, the 28-year-old has been patient for minutes, but has benefitted from his versatility, utilised in both defence and midfield in recent months.
On Boxing Day Saiss’ late equaliser earned Wolves a point against Fulham and the following month he opened the scoring in an impressive victory over West Ham United.
Last weekend he helped Wolves into their first FA Cup quarter final since 2003 and can look forward to to the future at Molineux.
On Saiss’ new deal, sporting director, Kevin Thelwell said: “We’re delighted that Romain has committed his future to Wolves and will remain part of the group for the future.
“Romain has been an important player for the football club, particularly over the past 18 months, and played a huge role is achieving promotion to the Premier League.
“Over the past two and a half seasons, Romain has progressed impressively alongside the football club and we’re looking forward to the future with him being a big part of the group.”
