O'Brien

O'Brien may refer to the following:


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


 * O'Brian (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.