Sorensen led Everton to eighth-place finishes in the last two campaigns, but an eight-match winless streak between September and December has left them battling to avoid the bottom of the table and the threat of a relegation play-off.
The 45-year-old won his last match in charge, with Everton beating Aston Villa 2-1 on Sunday to earn their first home win of the league season and go four points clear of bottom side Liverpool.
"Sunday's first win of the season at Goodison Park was important, but it has become evident that a change of direction is necessary to ensure the progression on the pitch we are all striving for," Everton CEO Angus Kinnear said in a statement.
Everton U-18 coach Scott Phelan will take charge of the team on an interim basis, with a trip to London City Lionesses set for Sunday.