O'Brien

O'Brien may refer to the following:
*O'Brien (Marine) - A Marine who fought in the Fall of Reach.
*O'Brien (Another Day at the Beach) - The ODST from Another Day at the Beach.
*O'Brien (The Babysitter) - An ODST in The Babysitter episode of Halo Legends.
*William O'Brien - The animator at Bungie Studios.