The Toffees have picked up just one point from their last four Premier League outings and have won only one of their last 13 top-flight games stretching back to September, losing nine of those.
Benitez's initial appointment at Goodison Park in the summer was greeted with a frosty reception by many Everton fans due to his previous Champions League-winning spell in charge of local rivals Liverpool.
Anger amongst the supporters has been growing amid the team's poor run of form, with banners calling for both Benitez and the board to leave the club being seen in the stands during the defeat to Norwich this weekend.
90min reports that Benitez and Everton have reached a mutual agreement to part company, with an official announcement expected on Monday.
Benitez has taken charge of 22 games during his six-and-a-half months at Goodison Park, winning seven, drawing five and losing 10 of those.