The men's singles SU5 tournament at the 2020 Summer Paralympics in Tokyo took place between 1 and 4 September 2021 at Yoyogi National Gymnasium.

[1] These were the seeds for this event:[2] The draw of the group stage revealed on 26 August 2021.

[3] The group stage was played from 1 to 3 September.

The top two winners of each group advanced to the knockout rounds.

The knockout stage was played on 4 September.