The Dec. 4-6 short format asphalt event, with some 220km of special stages involving the high-speed circuit and roads in the surrounding countryside, will stretch the championship to eight rounds.
It will be the second round held in Italy after this weekend's rally in Sardinia.
The country is also hosting three Formula One grands prix for the first time.
"As the final round of the championship, there’s a strong chance both the drivers’ and manufacturers’ WRC titles could go right down to the wire on Monza’s roads," said WRC promoter managing director Jona Siebel in a statement.
"This type of rally is rare in our championship but will provide a thrilling finale to an unpredictable year."
Rally Monza, an end of year event held since 1978 and bringing together rally, circuit and celebrity racers, has been won seven times in the past by MotoGP great Valentino Rossi.
Other past winners include ex-F1 racer Robert Kubica and rally great Sebastian Loeb. (Reporting by Alan Baldwin, editing by Toby Davis)