The men's 400 metres at the 2024 European Athletics Championships took place at the Stadio Olimpico from 8 to 10 June.

[1] All times are local times (UTC+2) The next 14 fastest (q) advanced to the semifinals.

The 10 highest ranked athletes received a bye into the semifinals.

[6] [7] [7] [7] The first 2 in each heat (Q) and the next 2 fastest (q) advance to the final.

[8] *Athletes that received a bye into the semifinal [9] [9] [9] The final started on 10 June at 21:40.