Ysgol Maesydderwen is a state secondary school and sixth form in Ystradgynlais, Powys.

The school was rated a mix of "good" and "adequate" in a 2017 Estyn report and amber in the 2019 national school categorization.

[4][5] In 2021 Estyn reported that the school had been removed from the list of schools requiring Estyn review, deeming it to have made sufficient progress in addressing the recommendations made in the 2017 inspection.

[6] In 2017, 9 per cent of pupils spoke Welsh at home.

This Welsh school or sixth form college related article is a stub.