The oedipus complex is thought to occur in which stage of psychosexual development?

Phallic.

Explanation:

The Oedipus complex is part of Freud's psychosexual theory. This theory states that as we grow old we go through different stages, and this stages start since the moment of birth and until adolescence and adulthood.

The stages are:

Oral An al Phallic Latency Genital.

The Oedipus complex is the most important characteristic of the phallic stage.

The name of this complex derives from a Greek myth in which Oedipus kills his father and marries his mother (unknowingly). Once he discovers what he did, he pokes his eyes and becomes blind.

According to Freud, children from 3 to 6 years old go through this Phallic stage and the conflict arises when the boy develops desires for his mother. Since he cannot take her mom as "spouse" the boy resolves this problem by imitating masculine dad-type behaviors and this is how boys resolve the Oedipus complex.