Simonis and his staff extended their contracts for one year, signing deals until June 2027.
"I am very happy about it," Simonis says on the club website. "I'm enjoying my time greatly at this great club. It was a very good proposal from the club, showing a lot of confidence and appreciation."
40-year-old Simonis is reportedly on Ajax's shortlist for the managerial job. Italian manager Francesco Farioli left the club last Monday, less than 24 hours after officially losing the Eredivisie title to PSV. With Simonis' extension, Ajax will likely have to move on.
Simonis joined the club in the summer of 2024 as he took on his first managerial job. The former Heerenveen assistant impressed with his Go Ahead Eagles side, showcasing a modern brand of attractive, attacking football en route.
Simonis earned a legendary status at the club after winning the KNVB Beker in April, the first major trophy in club history, following a penalty shootout win against AZ. The cup win secured the club a spot in the league phase of next season's UEFA Europa League, which will mark the first time Go Ahead Eagles will play European football since the 60s.
"We are also going into Europe with Go Ahead Eagles, wonderful. A great challenge awaits in the coming years!"