O'Brien

O'Brien may refer to the following:


 * O'Brien (Heian) - An ODST in The Babysitter episode of Halo Legends.


 * O'Brien (Marine) - A Marine who fought in the Fall of Reach.


 * O'Brien (Mombasa) - An ODST from Another Day at the Beach.


 * William O'Brien - An animator at Bungie Studios, also known as Bill O'Brien.