William John Sass-Davies (born 17 February 2000) is a Welsh professional footballer who plays for National League club Hartlepool United.

[14] Sass-Davies scored his first professional goal, for Crewe, in a 2–1 defeat to Lincoln City in the first round of the EFL Cup at Gresty Road on 5 September 2020.

[17] On 9 February 2021, Sass-Davies joined National League side Yeovil Town on a one-month loan deal,[18] making his debut in a 1–0 defeat at Eastleigh later the same day.

[22] Sass-Davies was sent off after 13 minutes of Crewe's second game of the 2021–22 season, an EFL Cup first round tie at Hartlepool United on 10 August 2021.

[29] On 1 September 2023, he and teammate Regan Griffiths joined National League side Boreham Wood on loan deals running to 31 January 2024.

[36] He was called up by the Wales national under-19 football team in September 2017 to play against Iceland,[37] starting four matches, including a UEFA European Under-19 Championship qualifier against Kazakhstan on 13 November 2017.

[42] In August 2021, Sass-Davies was called up for the under-21 side to play against Bulgaria in Sofia on 7 September 2021,[43] and scored the second goal in Wales's 4–0 victory.