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, the Leicestershire County Cricket Club and the Middlesex County Cricket Club.
He retired from all cricket in January 2012 due to chronic injury problems.