| Full Name: | James Vincent O'Brien |
| Birth Date: | 24 July 1925 |
| Birth Place: | Toronto, Ontario, Canada |
| Height: | 173 cm |
| Weight: | 68 kg |
| Sport: | Athletics |
| Event: | 100 m |
| Club: | Toronto West End YMCA |
| Pb: | 100 m – 10.6 (1948) |
James Vincent O'Brien (24 July 1925 – 27 May 1988), also known as "Jim" or "Jimmy", was a Canadian sprinter. He competed in the 100 m and 4 × 100 m events at the 1948 Summer Olympics and finished fifth in the relay. Besides athletics O'Brien played hockey and Canadian football. He retired from competitions a few years after the 1948 Olympics.