LGBT or GLBT is an abbreviation for lesbian, gay, bisexual and transgender people. The term has been used since the 1990s as an adaptation of the acronym LGB, which began to replace LGBT communities in the mid to late 1980s and gays. Activists believe that the term gay community does not accurately represent all the people it refers to.

When marking topics related to sex and gender identity, abbreviations have become the mainstream and the umbrella term. For example, in a comprehensive study of such centers around the United States, the LGBT campaign promotion program known as the LGBT community center is called the community center, which provides services specifically for LGBT community members. The LGBTQ Journalists Association promotes the use of the term LGBTQ, which refers to topics related to sexuality and gender identity for use by media in the United States and some other English speaking countries.

The original LGBT was designed to emphasize gender and cultural diversity based on gender identity. It can be used to refer to people who are not heterosexual or homosexual, rather than to people who are homosexual, bisexual or transgender. In recognition of this, a popular variant adds the letter Q to those who are labeled queer or question their sexual identity. "LGBTQ" has been recorded since 1996. Those who add bisexuals to LGBT groups or organizations use the extended acronym lgbti. Sometimes these two acronyms are combined to form the term LGBTIQ or LGBT +, to cover the range of sex and gender. There are other less common variants, including the desire for inclusion, which include variants more than twice the length, which have attracted criticism.