Stigma, originally referring to the visible marking of people considered inferior, has evolved to mean a negative perception or sense of disapproval that a society places on a group or individual based on certain characteristics such as their socioeconomic status, gender, race, religion, appearance, upbringing, origin, or health status. Social stigma can take different forms and depends on the specific time and place in which it arises. Once a person is stigmatized, they are often associated with stereotypes that lead to discrimination, marginalization, and psychological problems.

This process of stigmatization not only affects the social status and behavior of stigmatized persons, but also shapes their own self-perception, which can lead to psychological problems such as depression and low self-esteem. Stigmatized people are often aware that they are perceived and treated differently, which can start at an early age. Research shows that children are aware of cultural stereotypes at an early age, which affects their perception of their own identity and their interactions with the world around them.

Stigma (plural stigmas or stigmata) is a Greek word that in its origins referred to a type of marking or the tattoo that was cut or burned into the skin of people with criminal records, slaves, or those seen as traitors in order to visibly identify them as supposedly blemished or morally polluted persons. These individuals were to be avoided particularly in public places.

Social stigmas can occur in many different forms. The most common deal with culture, gender, race, religion, illness and disease. Individuals who are stigmatized usually feel different and devalued by others.

Stigma may also be described as a label that associates a person to a set of unwanted characteristics that form a stereotype. It is also affixed. Once people identify and label one's differences, others will assume that is just how things are and the person will remain stigmatized until the stigmatizing attribute is undetectable. A considerable amount of generalization is required to create groups, meaning that people will put someone in a general group regardless of how well the person actually fits into that group. However, the attributes that society selects differ according to time and place. What is considered out of place in one society could be the norm in another. When society categorizes individuals into certain groups the labeled person is subjected to status loss and discrimination. Society will start to form expectations about those groups once the cultural stereotype is secured.

Stigma may affect the behavior of those who are stigmatized. Those who are stereotyped often start to act in ways that their stigmatizers expect of them. It not only changes their behavior, but it also shapes their emotions and beliefs. Members of stigmatized social groups often face prejudice that causes depression (i.e. deprejudice). These stigmas put a person's social identity in threatening situations, such as low self-esteem. Because of this, identity theories have become highly researched. Identity threat theories can go hand-in-hand with labeling theory.

Members of stigmatized groups start to become aware that they are not being treated the same way and know they are likely being discriminated against. Studies have shown that "by 10 years of age, most children are aware of cultural stereotypes of different groups in society, and children who are members of stigmatized groups are aware of cultural types at an even younger age."

French sociologist Émile Durkheim was the first to explore stigma as a social phenomenon in 1895. He wrote: