"It was a difficult decision but one that was in the interest of Nuremberg and we were forced to take it," said sports director Martin Bader.
He said last week's 5-0 home defeat to Hamburg was the last straw.
"Unfortunately our German Cup exit and the five points from eight league games forced us to take this step," he said.
Wiesinger took over in December 2012 and led the team to a 10th place finish last season.
Youth coach Roger Prinzen would take over as interim coach before a permanent replacement was found, the club said.