| Jack McNab | |
| Birth Name: | John Alexander McNab |
| Birth Date: | 14 December 1895 |
| Birth Place: | Hastings, New Zealand |
| Death Place: | Hastings, New Zealand |
| Ru Position: | Flanker |
| Height: | 1.85 m |
| Weight: | 85 kg |
| Ru Nationalyears: | 1925 |
| Ru Nationalcaps: | 0 |
| Ru Nationalpoints: | (0) |
| Ru Provinceyears: | 1920–1925 |
| Ru Provincecaps: | 43 |
| Occupation: | Farmer |
John Alexander McNab (14 December 1895 – 23 July 1979) was a New Zealand rugby union player. A flanker, McNab represented at a provincial level, and was a member of the New Zealand national side, the All Blacks, in 1925. Considered unlucky to have missed selection for the 1924–1925 tour of Britain, Ireland and France, he was named in the team for the 1925 tour of New South Wales, but only appeared in one match against before contracting appendicitis.[1]