2024 All-Ireland Under-20 B Football Championship

The 2024 All-Ireland Under-20 B Football Championship was the inaugural staging of the All-Ireland Under-20 B Football Championship since its establishment by the Gaelic Athletic Association. The championship ran from 10 April to 18 May 2024.

The All-Ireland final was played at Páirc Tailteann in Navan on 18 May 2024 between Down and Westmeath, in what was their first ever meeting in the final. Down won the match by 1–10 to 0–10 to claim their first ever championship title.

Westmeath's Brian Cooney was the championship's top scorer with 4-18.