Discrimination against men based on gender has been observed in various areas, for example in the health and education sectors due to stereotypes that men are dangerous to women and children. In the legal system, men on average receive higher rates of incarceration and longer sentences than women for similar crimes. Research on sexism against men has been limited, and the topic is little discussed due to cultural biases.

Discrimination against men is sometimes called reverse sexism. Philosopher David Benatar uses the term "second sexism".

Researchers Alice Eagly and Antonio Mladinik introduced the women-are-wonderful effect in 1994 after they found that both men and women tend to attribute positive traits to women, with women showing a much more pronounced bias. Positive traits were attributed to men by both sexes too, but to a much lesser extent. They found this trend in their 1989 and 1991 studies, which used questionnaires distributed to students in the United States.

In an online survey conducted by Ipsos between 2022 and 2023, 48% of people believed that the promotion of women's rights has gone as far as discriminating against men. Conservative commentators sometimes claim there is a "war" on men and boys. Richard V. Reeves, author of the book Of Boys and Men, writes that a third of American men believe that they are discriminated against, and that South Korean men in their twenties are twice as likely to believe that discrimination against men is more severe than discrimination against women. According to Reeves, this is false, and men's problems are the result of broader societal shifts, not deliberate discrimination.

There is limited research about discrimination against men in the workplace, and the OECD often does not consider men when measuring gender equality. Eurofound's European Working Conditions Survey (EWCS) in 2015 showed that 1% of men and 3.1% of women had perceived discrimination in the past 12 months. Discrimination against men in regards to hiring typically happens in occupations which have the gender role of being feminine. One study found that discrimination against men in female-dominated workplaces is more prevalent than discrimination against women in male-dominated workplaces. Employers may consider that men taking time off means that they are not committed to their job, whereas women taking time off is considered normal. Discrimination can also take the form of stricter dress codes for men.

For a long time in the United States, the idea of discrimination against men was perceived by lawyers and judges as laughable. However, through the efforts of the lawyer Ruth Bader Ginsburg, the anti-stereotyping theory was developed. According to this theory, sex stereotyping, which is often experienced by both men and women in the workplace, can be considered sex-based discrimination. This approach has become the norm in US judicial practice after a landmark decision Price Waterhouse v. Hopkins. And the decision in Oncale v. Sundowner Offshore Services, Inc. has determined that it can also be considered sex-based discrimination when people discriminate against people of the same sex. The feminist movement has made a major contribution to the promotion of the anti-stereotyping principle.

In 2006 researchers of the English labour market sent out CVs with equal qualifications, ages and experience and concluded that the feminine gender role job of secretaries discriminated against men with hiring, but the study also found 'mixed occupations' with discrimination against men: trainee chartered accountants and computer analyst programmers. Some believe that this may be due to affirmative action.

According to the Observatory of Inequalities, in France men are put under more pressure in work, expected to work long hours and full time and have higher rates of accidents, which was described as reverse sexism.