List of ATP Big Titles singles champions

In men's tennis, the Grand Slam tournaments, the Masters tournaments, and the year-end championships are considered the top-tier events of the annual ATP Tour calendar, in addition to the quadrennial Olympics. They are collectively known as the 'Big Titles'. The ATP defined the mandatory events (Slams, Masters and YEC) as follows

They are the biggest tournaments in our sport, where participation is mandatory, entry is reserved for the world's best and success is rewarded with fame and a rich haul of points and prize money.

This article lists the respective singles champions of those events since the inception of the ATP Tour in 1990.

Note: By setting 1990 as the cut-off point, this list excludes many notable champions in top level tournaments from previous years. The Grand Slam tournaments and the year-end championships have been held since 1877 and 1970 respectively. The Olympics was first played in 1896, interrupted after 1924 and later resumed in 1988. High category tournaments equivalent to the Masters Series like the Grand Prix Super Series existed before the ATP Tour was introduced. There were also the professional Majors, the World Championship Series and the amateur Majors (WHCC, WCCC) before the Open Era.