Censor.NET reports citing AFP.
Arguably Russia's favourite director, millions know his iconic films from the 1960s and 1970s off by heart.
"My grandfather has passed away," Ryazanov's grandson Dmitry Troyanovsky wrote on Facebook.
Ryazanov suffered from poor health in recent years, including a stroke this month. His website has been overflowing with fans' tributes.
Born in Samara, a city on the Volga river, Ryazanov landed a spot at Moscow's prestigious Gerasimov film school (VGIK), starting his studies as the country was still deep in World War II fighting.
He became an overnight sensation after his first feature film "Carnival Night", a 1956 comedy in style of American musicals that was an instant box office hit with more than 45 million viewers.
Ryazanov' best-known comedy, "Irony of Fate", features a man who wakes up on New Year's eve in another city in a woman's home by mistake -- something made possible by Soviet Union's mass housing construction of identical apartment blocks all over the country.
The film is still shown on television every year on New Year's eve and was made into a popular spin-off.
Ryazanov continued working long after the Soviet Union fell apart, though his later films never achieved the same cult status. He also taught at the VGIK film school and was one of the founders of Kinosoyuz, a Russian cinema guild.
Along with other guild members, Ryazanov signed a letter in 2014 opposing Russia's military meddling in eastern Ukraine following Moscow's annexation of the Crimean peninsula.
"He made life less cruel and hopeless, more spiritual and, last but not least, more funny," film critic Andrei Plakhov wrote, calling Ryazanov "a great artist and citizen."