''Oz'' deals a lot with existentialism and philosophy in general, especially in Hill's narration. At the same time, almost every main character represents a different philosophical approach to dealing with life.

'''Adebisi''' represents Hedonism. His main way of dealing with his misery in Oz is through pleasure, either through sex, drugs, food, or violence. Adebisi's struggle for power is simply a way for him to get easy access to these pleasures. However, when he does achieve this goal, he's still unsatisfied, and can't enjoy the things he used to. In his own words, it can never be enough, because he's still ultimately in prison for life.

Both '''O'Reilly''' and '''Keller''' represent objectivism. They both believe that anything is necessary to achieve their goals, that their individual success is what matters most, and believe they are entitled to whatever they want.

'''Beecher''' by the end of the series represents absurdism. The struggle he goes through is extreme, but he ultimately takes meaning from this and uses it to discover his true self. He believes all life is precious, should be treated with respect, and that murder is never acceptable. Even in the worst of situations, life has meaning and should be valued.