Sociology of gender is a subfield of sociology. As one of the most important social structures is status (position that an individual possesses which affects how they are treated by society). One of the most important statuses an individual claims is gender. Public discourse and the academic literature generally use the term gender for the perceived or projected (self-identified) masculinity or femininity of a person.

The term gender role was coined by John Money in a seminal 1955 paper where he defined it as "all those things that a person says or does to disclose himself or herself as having the status of boy or man, girl or woman."

According to American gender theorist Judith Butler, a person's gender is complex, encompassing countless characteristics of appearance, speech, movement and other factors not solely limited to biological sex. Many societies have binary gender systems in which everyone is categorized as male or female. Some societies include a third gender role; for instance, the Native American Two-Spirit people and the Hijras of India. There is debate over the extent to which gender is a social construct or a biological construct.

In the 1960s and 1970s, the women's movement started the momentum that led to the formation of feminist theory. One of the publications that launched this movement was Betty Friedan's The Feminine Mystique. This book described how women were expected to be fulfilled throughout their housework, immediately resonated with many women as it became a bestseller, and a movement was ignited. During this movement, also known as the women's rights movement or women's liberation movement, women fought for equal rights, and more personal freedom in all aspects of life such as politics, work, family and sexuality. In June 1966, the National Organization for Women (NOW) was created by women's rights activists Betty Friedan, Pauli Murray, Shirley Chisholm, and Muriel Fox to advocate political and social equality for women. Although the organization did not succeed right initially, by 1969, NOW was more comfortable with lobbying for women's reform in Washington. In 1972, Congress passed the Equal Rights Amendment (ERA). Despite it being a victory for feminism, the passage of the ERA led to criticism from anti-feminists, who argued that the ratification of the ERA would result in the invalidation of sodomy laws, and would lead to the legalization of same-sex marriage. The ERA needed to be ratified by 38 states in ten years, and fell short by three. This occurred in the second wave of feminism, after the first wave in the 19th for women's suffrage, and the foundation of early feminist theory.

During the 1970s, there was no consensus about how the terms were to be applied. In the 1974 edition of Masculine/Feminine or Human, the author uses "innate gender" and "learned sex roles", but in the 1978 edition, the use of sex and gender is reversed. By 1980, most feminist writings had agreed on using gender only for sociocultural adapted traits.

Feminist theory is a broad term for a variety of theories which all emphasize women's experiences and the belief that society is subordinate to women. Liberal feminism is the belief that individuals should be free to develop their own talents and pursue their interests. Individuals seek to expand equality by removing the barriers in society. Socialist feminism believes that capitalism strengthens patriarchy by concentrating wealth and power in the hands of a few, and the traditional family structure should be replaced by a collective revolution. In radical feminism, they believe that patriarchy is so deeply rooted in society that even a sociological revolution would not end it; society must eliminate gender itself.

Early feminist theory targeted sex and gender and the injustices based on these gender categories. However, the early feminist movement was geared towards the equality for white middle-class women, and excluded other minority women, especially black women. Minority women face different experiences and struggles from white middle-class women, but this was largely overlooked in early feminist theory. However, this theory allowed for the birth of feminism, which focuses on women's empowerment, freedom, and the enhancement of a woman's sense of self. As time progresses, feminism can be broken into four distinct waves: first-wave from the 19th to early 20th century, second-wave feminism from the 1960s to 1970s, to the third and fourth waves of feminism from the 1990s to now. Each wave of feminism has its own goal that focused on the importance of equality among men and women in regards to social, political, and economic equality. In the first wave, feminists focused on women's suffrage, or giving women the right to vote. It was a movement that pushed for political equality so that women could participate in politics. But in this movement, it mainly advocated for the right to vote for white women, while excluding minority women. The exclusion of minority women in first movement sparked the acknowledgement of minority groups in the second movement. However, the second movement mainly dealt with sexuality and reproductive rights.  The movement worked toward the passing of the Equal Rights Amendment, which was designed to guarantee equal rights for everyone regardless of their sex. By the end of this wave, society began to realize that gender, the idea of what it means to be a "woman", and society's expectations of what a woman is, are socially constructed. This realization led to the rise of the third feminist movement. It focused on debunking the predominant idea society held for women and their position in society. In this movement, the notion of being "girly" or "feminine" is broken down to redefine society's definition of a woman. The boundaries of gender are reconstructed to allow people to experiment with the fluidity of gender. However, this movement also combats the sexism and patriarchy, or the system in which men hold all the power. This is shown through the domination of sexist culture, where women are looked down upon for the same actions or experiences men partake in.

The fourth wave of feminism began in 2013 and centers around sexual harassment, rape culture, and body shaming. One of the major distinctions in this wave is the use of social media and the internet to spread its messages. This wave erupted after a young woman in India died after being brutally gang raped. Another catalyst to this wave of feminism was the election of president Donald Trump in 2016 after his remarks about women. One day after President Trump's inauguration, in 2017, about 4.6 million people took to the streets of Washington, DC, to the Women's March to protest gender equality. Also in 2017, the Me Too movement gained popularity, in which women came forward to share their experiences of sexual assault after it became known that Harvey Weinstein sexually assaulted women for years in the film industry. This movement grew in only a couple of months to condemn powerful men in business, politics, news, and entertainment for their assaults against women.