The Italian international, 29, has been repeatedly linked with a move to Fiorentina this summer.
However, Giaccherini has made it clear that he intends to honour the remaining three years of his contract with the Black Cats.
"Fiorentina have followed me in the past but I have never had concrete contact," he is quoted as saying by Sky Sports News. "I'm happy at Sunderland. I have three more years on my contract.
"I'm enjoying this experience in England and this season I hope to do better than last year."
Giaccherini scored five goals in 32 games for Sunderland during the 2013-14 campaign.