This study examines the influence of gender on aggression, anxiety, and depression among 700 undergraduates (350 males, 350 females; mean age = 19.85 years) drawn via stratified random sampling from five universities in South-Eastern Nigeria. Aggression was measured using the Buss Perry Aggression Questionnaire (BPAQ) (Buss & Perry, 1992), anxiety with the State–Trait Anxiety Inventory Y‑1 (STAI Y‑1) (Spielberger, 1983), and depression with the Self‑rating Depression Scale (SDS) (Zung, 1965). The results indicate that female participants exhibited significantly higher levels of aggression (F(1,700) = 45.72, p < .05) and depression (F(1,700) = 34.43, p < .05), whereas gender differences for anxiety were non‐significant (F(1,700) = 1.84, p > .05). These findings underscore the importance of gender as a determinant in psychosocial outcomes within tertiary student populations in Nigeria.