Ghana defender Jeff Schlupp will work under a new manager at Crystal Palace after rank De Boar was sacked on Monday.
The Dutchman has paid the heavy prize for the side's unflattering start to the Premier League campaign.
He has been relieved off post after just five games in charge and 77 days in charge.
"Crystal Palace Football Club have this morning parted company with Frank de Boer." a club statement read
"We would like to thank Frank for his dedication and hard work during his time at the Club.
"A new manager will be appointed in due course and we wish Frank the very best of luck for the future.
"There will be no further comment at this time."
The former Ajax boss, 47, only took over this summer, succeeding Sam Allardyce, who left after helping Palace avoid relegation last season.
His only win as Palace manager came in the EFL Cup against Ipswich Town.