Iain Edward O'Brien (born 10 July 1976) is a former New Zealand cricketer, who played 22 Tests, 10 ODIs and 4 T20Is. A pace bowler, he took 73 test wickets with best figures of 6 for 75 against West Indies in 2008. He played first class cricket for Wellington, Leicestershire County Cricket Club and Middlesex County Cricket Club.
| Format | Matches | Runs | Avg | 100s/50s | Top Score | Wickets | Bowl Avg | Best Bowling | Catches/St |
| Test | 22 | 219 | 7.55 | 0/0 | 31 | 73 | 33.27 | 6/75 | 7/– |
| ODI | 10 | 3 | – | 0/0 | 3* | 14 | 34.85 | 3/68 | 1/– |
| FC | 91 | 756 | 8.68 | 0/0 | 44 | 322 | 26.06 | 8/55 | 17/– |
| LA | 58 | 99 | 24.75 | 0/0 | 19* | 75 | 31.41 | 5/35 | 9/– |
