Athletics at the 2021 Summer World University Games – Men's 400 metres

The men's 400 metres event at the 2021 Summer World University Games was held on 1, 2 and 3 August 2023 at the Shuangliu Sports Centre Stadium in Chengdu, China.

Round 1
Qualification: First 3 in each heat (Q) and the next 6 fastest (q) advance to semifinal.

Semifinal
Qualification: First 2 in each heat (Q) and the next 2 fastest (q) advance to final.