Jose Mourinho has signed the 33-year-old for the third time, having brought him back to Chelsea in 2014 and then to Manchester United three years later.
The former Serbia international left Old Trafford earlier this month after his contract expired.
Manchester United midfielder has signed a one-year contract with Roma
Matic will wear the number 21 shirt for the Europa Conference League winners until his contract expires in June 2023.
“Not only does Nemanja bring a lot of quality on the pitch to Roma, but he also offers a wealth of experience from so many seasons in the Premier League, as well as a focus and mindset that has continually set him apart throughout his career,” stated the club’s general manager, Tiago Pinto.
“His excitement at the thought of joining our project was really encouraging, and I am confident that this will serve as the beginning of a very fruitful journey for all of us.”