Vialli was diagnosed with pancreatic cancer in 2017 but successfully underwent chemotherapy and made a full recovery in 2020.
The disease resurfaced in 2021.
Vialli had notable playing spells with Cremonese, Sampdoria, Juventus and Chelsea.
He won one Serie A title each with Sampdoria and Juventus, also winning the UEFA Champions League with the Old Lady in 1996.
He won the FA Cup as a player and also as a manager during his spell in England with Chelsea.
Vialli won 59 caps for the Italy national team and was part of the side that finished third at the 1990 FIFA World Cup on home soil.
Vialli's former clubs have been paying tribute since his death was confirmed.
Sampdoria said in a statement: "We won't forget your 141 goals , your overhead kicks, your cashmere shirts, your earring, your platinum blonde hair, your Ultras bomber jacket. You gave us so much, we gave you so much: yes, it was love, reciprocal, infinite. A love that will not die today with you."
A Juve statement said: "We loved everything about you, absolutely everything - your smile, your being a star and leader at the same time, on the pitch and in the dressing room, your adorable swashbuckling ways, your culture, your class, which you showed until the last day in the black and white stripes."
"Gianluca was a splendid person and he leaves a void that cannot be filled," said Italian Football Federation (FIGC) president Gabriele Gravina.
"I hoped until the end that he would be able to perform another miracle. Yet I am comforted by the certainty that what he did for Italian football and the blue shirt will never be forgotten."
