The former Ireland manager, who in November had signed a 19-month contract to May 2022, was fired following the side's 2-1 loss to Doxa on Sunday.
"APOEL announces it is ending its cooperation with coach Mick McCarthy. We wish Mr McCarthy and his assistant Terry Connor all the best," the club said in a short statement.
McCarthy, a former Ireland international, twice coached Ireland as well as Sunderland, Wolverhampton Wanderers, and Ipswich in England.
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APOEL, the island’s most successful club, were 10th in the 14-team league when McCarthy took over in November, with two wins from eight games.
Under McCarthy they fared no better, however, managing only two more wins from their next eight league games, leaving them now in 11th place.
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