Two lower Italian courts had found the two guilty of failing to declare millions of euros the company had earned through a subsidy based in Luxembourg.
In April, they had been sentenced to a suspended 20-month jail term, reports The BBC.
Mr Dolce and Mr Gabbana have always denied the charges.
In June 2013, they were convicted by a lower court for failing to file tax declarations for the Luxembourg company, Gado, which prosecutors alleged was set up to evade paying taxes in Italy.
The two denied the charges, and last year they briefly closed their Milan stores in protest.
The ruling by Italy’s top court is the final ruling on the subject.
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