| William Collis | |
| Full Name: | William Stewart Collis |
| Birth Date: | 27 September 1860 |
| Birth Place: | Dublin, Ireland |
| Death Place: | Killiney, Dublin Ireland |
| Occupation: | Solicitor |
| Relatives: | John Collis (son) Maurice Collis (son) Robert Collis (son) |
| Position: | Forward |
| Repyears1: | 1884 |
| Repcaps1: | 1 |
| Reppoints1: | 0 |
William Stewart Collis (27 September 1860 — 2 January 1947) was an Irish international rugby union player.
A Dublin solicitor, Collis played rugby during his youth and received an Ireland cap in 1884, playing as a forward against Wales at Cardiff. He was the head of Collis & Ward Solicitors.[1]
Collis's son Robert was also an Ireland rugby international. Robert's twin brother was the writer John Stewart Collis and another son, Maurice Collis, was a colonial administrator in Burma.[2]