His chief works include ‘ Llyn y Fan ,’ first performed at the national eisteddfod of Wales at Swansea in 1907 , and again at Wrexham in 1912 ; ‘ A Song for St. Cecilia's Day ’ ( Queen's Hall , London , 1909 ); and ‘ The Bard ’ ( Queen's Hall , London , 1912 ). He wrote a large number of anthems, songs, and part songs, for both Welsh and English lyrics, and left a considerable body of instrumental work, most of which is still unpublished.

As a composer Vaughan Thomas is best remembered for the originality and scholarship which he brought to his settings of Welsh poetry, especially in his ‘ Saith o Ganeuon .’ Less well known, but equally notable for their lyrical beauty, are his songs on English words by George Meredith . Vaughan Thomas was a pioneer in the movement to lead Welsh music forward from a limited choralism to a more sensitive practice and appreciation of other musical forms. In his lectures and recitals, and in his programme planning for the national eisteddfod, he gave a vigorous lead towards new standards.

The work of Vaughan Thomas is pervaded by an imaginative enthusiasm for the characteristic qualities of a national culture and their distinctive expression in music.