Oakley is particularly well known for his work on professional ethics and also the so-called 'problem' of friendship. The problem of friendship looks at how a strict application of impartialist ethical doctrines, such as utilitarianism and Kantianism, conflicts with our notions of friendship or 'true friendship'. In 1995, he published, with Dean Cocking, the now widely cited article "Indirect Consequentialism, Friendship, and the Problem of Alienation" in the journal ''Ethics''.