Effective strategies for mental disorders prevention and its risk factors' reduction cannot be gender neutral, while the risks themselves are gender specific. This paper aims to discuss why gender matters in mental health, to explain the relationship of gender and health-seeking behaviour as a powerful determinant of gender differences, to examine the gender differences in common mental health disorders, namely, depressive and anxiety disorders, eating disorders, schizophrenia, and domestic violence, and finally, to raise some recommendations stemming from this review.