The Monte Carlo Masters, known as the Rolex Monte Carlo Masters for sponsorship reasons, is a men's tennis tournament belonging to the ATP Tour Masters 1000 category, which is the most important category after the four Grand Slam tournaments and the ATP Finals.

The competition takes place in April on the clay courts of the Monte Carlo Country Club in Roccabruna, a French municipality bordering the Principality of Monaco.

It was voted by ATP tennis players as the best category tournament in 2001 and 2007.

The Monte-Carlo Masters is one of the major tennis tournaments played on clay. It was founded in 1897 and in the first editions it saw the victory of the British Reggie Doherty, multiple winner of the Wimbledon Tournament. Reggie defended the title for three consecutive years before handing it over to his brother Lawrence in 1900.

The tournament became Open starting from 1969. The 2020 edition is not played due to the COVID-19 pandemic.