LGBTQ slang, LGBTQ speak or queer slang is a set of English slang lexicon used predominantly among LGBTQ people. It has been used in various languages since the early 20th century as a means by which members of the LGBTQ community identify themselves and speak in code with brevity and speed to others.

LGBTQ slang has played an integral part in LGBTQ culture for decades. Slang language initially emerged as a way for queer people to communicate with one another while avoiding detection by mainstream society. Queer people have always existed, but historically, they have had to be discreet about their identities and lives, particularly when being LGBTQ was illegal and or socially condemned.

LGBTQ slang is used as a way to signal one's identity and build solidarity within the community. When queer people use these certain words and phrases, they demonstrate to others that they are part of the LGBTQ community and share a common experience. This connection can create a sense of belonging for those historically rejected and isolated by mainstream society.

LGBTQ slang is also used by the community as a means of reclaiming language and deconstructing oppressive norms. Queer slang often includes playful references to sexual acts, which can serve as an assertion of sexual agency and a rejection of shame.

Because of sodomy laws and threat of prosecution due to the criminalization of homosexuality, LGBTQ slang has served as an argot or cant, a secret language and a way for the LGBTQ community to communicate with each other publicly without revealing their sexual orientation to others. Since the advent of queer studies in universities, LGBTQ slang and argot has become a subject of academic research among linguistic anthropology scholars.

During the first seven decades of the 20th century, a specific form of Polari was developed by gay men and lesbians in urban centres of the United Kingdom within established LGBTQ communities. Polari was featured on the BBC radio programme Round the Horne in 1964, exposing the wider public to the secret language. Although there are differences, contemporary British gay slang has adopted many Polari words. The 1964 legislative report Homosexuality and Citizenship in Florida contains an extensive appendix documenting and defining the homosexual slang in the United States at that time. SCRUFF launched a gay-slang dictionary app in 2014, which includes commonly used slang in the United States from the gay community. Specialized dictionaries that record LGBTQ slang have been found to revolve heavily around sexual matters.

Slang is ephemeral; terms used in one generation may pass out of usage in another. For example, in the 1960s and 1970s, the terms "cottage" (chiefly British) and "tearoom" (chiefly American) were used to denote public toilets used for sex. By 1999, this terminology had fallen out of use to the point of being greatly unrecognizable by members of the LGBTQ community at large.

Many terms that originated as gay slang have become part of the popular lexicon. The word drag was first used by William Dorsey Swann, a freed African American slave. Swann referred to himself as the "queen of drag" in the 1880s and 1890s. Drag was later popularized by Hubert Selby Jr. in his book Last Exit to Brooklyn. Drag has been traced back by the Oxford English Dictionary (OED) to the late 19th century. Conversely, words such as "banjee", while well-established in a subset of gay society, have never made the transition to popular use. Conversations between gay men have been found to use more slang and fewer commonly known terms about sexual behavior than conversations between straight men.