The men's hammer throw at the 2021 World Athletics U20 Championships was held at the Kasarani Stadium on 18 and 20 August.

[1] The qualification took place on 18 August, in two groups, with Group A starting at 09:08 and Group B starting at 10:36.

Athletes attaining a mark of at least 74.00 metres ( Q ) or at least the 12 best performers ( q ) qualified for the final.

[2][3] The final was held on 20 August at 16:17.

[4]