RAI state TV, which produced popular television versions of his detective stories, interrupted programming to announce his death on Wednesday morning.
Rome’s hospital system also announced the death, a month after he suffered a heart attack and was admitted to hospital in a critical condition.
His books, most set in his native Sicily, sold 25 million copies in Italy, and he also had legions of readers overseas thanks to the enduring popularity of his character, police chief Salvo Montalbano.
The TV adaptation of Montalbano’s adventures, which starred Luca Zingaretti, further propelled Camilleri’s popularity.
Repeats of the show consistently recorded the highest audience ratings and shows were also exported to Latin America, Australia and across Europe.
Camilleri was a regular best-selling author in Italy and often had several books high in the ranking in the same week.
He was also becoming increasingly popular in the UK – with BBC Four broadcasting the Montalbano TV series from mid-2011.
However, he did not publish his first book until he was 70 years old, previously working as a successful theatre and TV director and scriptwriter. He produced his 100th book in 2016 at the age of 90.
“After 30 years in the theatre as a director, dialogue for me becomes fundamental in the structure of the novel,” Camilleri told the Associated Press in an interview in his Rome apartment in 2009.
Following his death, Italy’s deputy prime minister Matteo Salvini expressed his condolences on Twitter.
He wrote: “Goodbye to Andrea Camilleri, Montalbano’s father and tireless narrator of his Sicily.”
David Sassoli, president of the European Parliament, also tweeted: “‘Words that speak the truth have a different vibration to all others.’ Farewell to Andrea Camilleri. You gifted us the love of reading.”
Fans have also been paying tribute on social media.
Rachel Roddy said: “So so sad to hear Andrea Camilleri was died, he helped me understand Sicily, its beauty and brutality, with wit, ingenuity and food grandissimo man and writer.”
Camilleri’s works were translated into 30 languages, including Chinese.
Harvard University romance languages professor Francesco Erspamer said he did not believe “there has ever been another Italian author with so many books translated into English” in such a short space of time.