​

A gender role, also known as a sex role, is a social role encompassing a range of behaviors and attitudes that are generally considered acceptable, appropriate, or desirable for people based on their biological or perceived sex. Gender roles are usually centered on conceptions of masculinity and femininity,

The World Health Organization defines gender roles as "socially constructed roles, behaviors, activities and attributes that a given society considers appropriate for men and women". Debate continues as to what extent gender and gender roles are socially constructed, and to what extent "socially constructed" may be considered synonymous with "arbitrary" or "malleable". Therefore, a concise authoritative definition of gender roles or gender itself is elusive.

In the sociology of gender, the process whereby an individual learns and acquires a gender role in society is termed gender socialization.

Gender roles are culturally specific, and while most cultures distinguish only two, others recognize more. Androgyny, for example, has been proposed as a third gender. Androgynous is simply a person with qualities pertaining to both the male and female gender. Other societies have claimed to identify more than five genders, and some non-Western societies have three genders – man, woman, and third gender. Some individuals identify with no gender at all.

Many transgender people reject the idea that they are a separate third gender, and identify simply as men or women. However, biological differences between trans women and cisgender women have historically been treated as relevant in certain contexts, especially those where biological traits may yield an unfair advantage such as sport.

Gender role, which refers to the cultural expectations as understood by gender classification, is not the same thing as gender identity, which refers to the internal sense of one's own gender, whether or not it aligns with categories offered by societal norms. The point at which these internalized gender identities become externalized into a set of expectations is the genesis of a gender role.

Some theories – which are collectively termed social construction theories – claim that gender behavior is mostly due to social conventions, although opposing theories disagree, such as theories in evolutionary psychology.

Most children learn to categorize themselves by gender by the age of three. From birth, in the course of gender socialization, children learn gender stereotypes and roles from their parents and environment. In a traditional view, males learn to manipulate their physical and social environment through physical strength or dexterity, while girls learn to present themselves as objects to be viewed. Social constructionists state, for example, that gender-segregated children's activities create the appearance that gender differences in behavior reflect an essential nature of male and female behavior.

As an aspect of role theory, gender role theory "treats these differing distributions of women and men into roles as the primary origin of sex-differentiated social behavior, their impact on behavior is mediated by psychological and social processes.