How mental health affects males is a topic of increasing interest within psychiatric research. This stems not only from public health campaigns looking at male suicide rates but also campaigns on so-called cultures of ‘toxic masculinity’; a sociological concept suggested to be behind the creation of environments endorsing antisocial behaviour such as violence and sexual assault (see also Chapters 15 and 17). However, when first deciding to study epidemiology and modifying risk factors in the development of psychopathology in males, we must establish a way of measuring a socially constructed concept that varies hugely dependent on culture. In this chapter we explore the concept of gender identity and roles in society, its difference from biological sex, and how the concept of gender varies between cultures. By looking specifically at gender, we can then begin to investigate the stresses that can occur from psychosocial gender constructs and how these may contribute to male mental health problems and other risk behaviours. Of noticeable importance are the higher rates of psychiatric illness among male migrants along with other contributing factors such as sexual orientation in the development of mental illness. The clinical implications for identifying at-risk individuals and providing treatment in the area of male mental health, is discussed. A key aspect that must be remembered is that there are challenges in definition of gender and non-binary divisions (see also Chapter 8).