Malcolm O'Kelly (born 19 July 1974) is an Irish former rugby union player who played as a lock for Ireland and Leinster.

O'Kelly was born in Chelmsford, England, and attended Templeogue College secondary school in Dublin, Ireland.

The 6-foot-8-inch (2.03 m) O'Kelly, who made his international début in 1997 against New Zealand, became a talisman of the Irish side and was Ireland's all-time caps leader,[citation needed] surpassing Mike Gibson, on 12 February 2005 when he started in Ireland's Six Nations fixture against Scotland.

He has won a grand slam, the Heineken cup, the Magners League(3) and 4 Triple Crowns: he is also Ireland's third most capped second row.

O'Kelly is a supporter of the children's charity Plan Ireland[4] and is a committee member of the rugby sevens club, Shamrock Warriors RFC.