The Wales national under-21 football team, also known as the Wales U21s, is the national under-21 football team of Wales and is controlled by the Football Association of Wales. The team competes in the UEFA European Under-21 Football Championship, held every two years. To date Wales haven't yet qualified for the finals tournament but in recent years have shown good form, losing in a playoff (5–4) to England in the 2009 qualifying campaign and finishing second in their group two years later, after leading their group until their last game Wales only needed a draw to qualify for the play-offs but lost 1–0 away to Italy.

The under-21 team came into existence following the realignment of UEFA's youth competitions in 1976. A goalless draw in a friendly against England at Wolverhampton Wanderers' Molineux Stadium was Wales U21s' first result.

The national under-21 team is the highest level of youth football in Wales, and is open to any players who were born in Wales or whose parents or grandparents were born in Wales. This team is for Welsh players aged 21 or under at the start of a two-year European Under-21 Football Championship campaign, so players can be, and often are, up to 23 years old. Also in existence are teams for Under-20s (for non-UEFA tournaments), Under-19s and Under 17s. As long as they are eligible, players can play at any level, making it possible to play for the U21s, senior side and again for the U21s.

Echipa de fotbal a Țării Galilor sub 21 de ani (în galeză: Tîm pêl-droed cenedlaethol dan-21 Cymru) reprezintă Țara Galilor în competițiile internaționale de fotbal pentru tineret și este controlată de Asociația de Fotbal a Țării Galilor, organismul de conducere pentru fotbal în Țara Galilor. A fost formată în 1976 și, începând cu 1992, a concurat la Campionatul European de Fotbal sub 21 UEFA.

Țara Galilor sub 21 de ani a jucat la Campionatul European de Fotbal sub 21 UEFA de șase ori, cea mai bună performanță fiind calificarea în semifinale în 1978. Echipa nu s-a calificat niciodată la Cupa Mondială FIFA sub 20.

Jucători notabili care au reprezentat Țara Galilor sub 21 de ani includ Aaron Ramsey, Gareth Bale, Joe Allen și Ben Woodburn.