The word "topless" usually refers to a woman who is naked above her waist or hips or, at least, whose breasts are exposed to public view, specifically including her areola and nipples. It can describe a woman who appears, poses, or performs with at least her breasts exposed, such as a "topless model" or "topless dancer", or to an activity undertaken while not wearing a top, such as "topless sunbathing". It may indicate a designated location where one might expect to find women not wearing tops, such as a "topless beach" or "topless bar". It can also be used to describe a garment that is specifically designed to reveal the breasts, such as the "topless swimsuit" (also known as the monokini) designed by Rudi Gernreich in the 1960s.

The word "topless" may carry sexual or exhibitionist connotations. Because of this, advocates of women's legal right to uncover their breasts wherever men may go bare-chested have adopted the alternative term "topfree", which is not perceived to have these connotations.

Attitudes towards toplessness have varied considerably across cultures and over time. The lack of clothing above the waist for both females and males was the norm in traditional cultures of North America, Africa, Australia and the Pacific Islands until the arrival of Christian missionaries, and it continues to be the norm in many indigenous cultures today. The practice was also the norm in various Asian cultures before Muslim expansion in the 13th and 14th centuries.

India

In many parts of northern India before the Muslim conquest of India, upper-class women in Maharashtra and the Ganges basin were fully clothed, while lower-class women were topless. Malayali people of Kerala required Hindu women other than Brahmins , Kshatriya and Syrian Christian class to strip to waist in public until 1858 when the Kingdom of Travancore granted all women the right to cover their breasts in public.

Toplessness was the norm for women among several indigenous peoples of South India until the 19th or early 20th century, including the Tamils along the Coromandel Coast, Tiyan and other peoples on the Malabar Coast, Kadar of Cochin Island, Toda, Nayar, Cheruman (Pulayar), Kuruba, Koraga, Nicobarese, and the Uriya.

Thailand

In Thailand, the government of Field Marshal Plaek Pibulsonggram issued a series of cultural standards between 1939 and 1942. Mandate 10 issued on 8 September 1941 instructed Thai people to not appear in public places "without being appropriately dressed". Inappropriate dress included "wearing no shirt or wearing a wraparound cloth". Before the introduction of Western dress codes, Thai women were depicted both fully clothed and topless in public. Until the early 20th century, women from northern Thailand wore a long tube-skirt (Pha-Sin), tied high above their waist and below their breasts, which were uncovered. In the late 19th century the influence of missionaries and modernization under King Chulalongkorn encouraged local women to cover their breasts with blouses.

Laos

In Laos, Henri Mouhot took a picture in 1858 of Laotian women that depicted virgins with clothed breasts and married women with their entire breasts exposed in public, because the baring of breasts for breastfeeding was considered to be nonsexual.

Indonesia

In the Indonesian region, toplessness was the norm among the Dayak, Javanese, and the Balinese people of Indonesia before the introduction of Islam and contact with Western cultures. In Javanese and Balinese societies, women had gone topless to work or rest comfortably. Among the Dayak, only big breasted women or married women with sagging breasts covered their breasts because their breasts interfered with their work.

Middle East

In most Middle Eastern countries, toplessness has not been socially accepted since at least the beginning of Islam (7th century), because of Islamic standards for female modesty. However, toplessness was the norm in some pre-Islamic cultures in Arabia, Egypt, Assyria and Mesopotamia. Tunisia and Egypt are an exception among Arabic states, allowing foreign tourists to swim topless on private beaches.

Africa

Among Himba women of northern Namibia and Hamar of southern Ethiopia, besides other traditional groups in Africa, the social norm is for women to be bare-breasted. Female toplessness can also constitute an important aspect of indigenous cultural celebrations. For example, in the annual Reed Dance festival mature girls between the ages of 16 and 20 dance topless before the Zulu king.

Australia

Traditional topless practices can lead to cross-cultural and legal conflict. In 2004, Australian police banned members of the Papunya community from using a public park in the city of Alice Springs to practice a traditional Aboriginal dance that included topless women.

South Pacific

In the South Pacific, toplessness was common prior to contact with Western missionaries, but is less common today. On the French territory of Moorea, toplessness is common. In the Marshall Islands, women were traditionally topless before contact with Western missionaries and still do not sexually objectify female breasts as is common in much of Western society. Marshall Island women typically swim in their muumuus which today are made of a fine polyester that dries quickly. Wearing of bikinis and one-piece, breast-covering swimsuits in the Marshall Islands is mainly seen at Western, restricted-access beaches and swimming pools like those at private resorts or on United States government facilities on the Kwajalein Atoll within the Ronald Reagan Ballistic Missile Defense Test Site.

In much of contemporary Western society, it is not culturally acceptable for women to expose their nipples and areola in public. In most Western societies, once girls enter adolescence, it is the social norm for them to behave modestly and cover their breasts in public. Until recent times, women who went topless were cited for indecent exposure or lewd. Women and the law in most western countries generally do not regard breasts as indecent. However, wearing a top in public is a social norm and most women are reluctant to go against it. The strictness of the etiquette varies depending on the social context. For example, at specific cultural events the norm may be relaxed, such as at Fantasy Fest, at Mardi Gras in New Orleans and at the Carnaval in Rio de Janeiro. The same may also apply at designated topless beaches.

Public breast-baring fashions

In many European societies between the Renaissance and the 19th century, exposed breasts were acceptable while a woman's bared legs, ankles or shoulders were considered risqué. During the Renaissance, many artists were strongly influenced by classical Greek styles and culture, and images of nude and semi-nude subjects in many forms proliferated in art, sculpture and architecture of the period. In aristocratic and upper-class circles the display of breasts also invoked associations with classical Greek nude sculptures and art and a classic breast shape was at times regarded as a status symbol, as a sign of beauty, wealth or social position. To maintain youthful-looking bosoms women could employ wet nurses to breastfeed their children.

Breast-baring female fashions have been traced to 15th-century courtesan Agnès Sorel, mistress to Charles VII of France, whose gowns in the French court sometimes exposed one or both of her breasts. (Jean Fouquet's portrayal of the Virgin Mary with her left breast uncovered is believed to have taken Sorel as a model.) Aristocratic women sought to immortalise their breasts in paint, as in the case of Sim