Sir John Rhŷs,[needs IPA] FBA PC (also spelled Rhys;[1] 21 June 1840 – 17 December 1915) was a Welsh scholar, fellow of the British Academy, Celticist and the first professor of Celtic at Oxford University.

[3] Rhŷs also travelled and studied in Europe during this period, staying in Paris, Heidelberg, Leipzig, and Göttingen.

He attended lectures by Georg Curtius and August Leskien while in Leipzig, and it was during this period that his interest in philology and linguistics developed.

In 1872 Rhŷs married Elspeth Hughes-Davies and together they had three children: Gwladus (born 1873, died as an infant), Myvanwy, and Olwen.

The Oxford Dictionary of National Biography declares him to be "foremost among the scholars of his time" in his published fields, noting that "his pioneering studies provided a firm foundation for future Celtic scholarship and research for many decades.

[9] The daughter of Rhŷs and his wife Elspeth, Myfanwy, attended the University College of North Wales in Bangor where she lived at the women's hall.