It opened in 1956, initially at Rhyl on the coast before moving inland to St Asaph in 1969.

[3] A government inspection reported that although 70% students are from homes where English is the main or only language spoken, 95% of the students spoke Welsh as well as a native speaker.

All subjects are taught in Welsh apart from English and a few in the sixth form.

[4] Musical theatre is important in Ysgol Glan Clwyd.

The school has recently put on a musical under the name of Sioe Y Sioeau, which included songs from The Lion King and Hairspray.