David W. E. Willis, FBA is a linguist and Celticist.

In 2020 he took up the post of Jesus Professor of Celtic at the University of Oxford.

[1] He had previously held posts in historical linguistics at the University of Manchester[2] and at the University of Cambridge, where he was a Fellow of Selwyn College.

The synchronic and diachronic syntax of Welsh has been a particular focus: his first book was on the loss of verb-second in the history of Welsh, and he has co-authored a textbook on the syntax of the present-day language.

He is also an expert in the syntax of negation and on Jespersen's cycle cross-linguistically.