The 22-year-old singer was set to perform at Portugal's popular festival, Rock in Rio.
Grande took to Instagram to inform her fans about the cancellation, according to The Hollywood Reporter.
"I'm deeply saddened to tell my babes in Portugal that I have to cancel my performance at Rock in Rio. (I've literally been crying over this for an hour)... I have a throat & sinus infection & my doctors have advised me not to sing for a few days," Grande wrote.