Butch is an identity used in LGBT+ subculture to describe someone, typically a lesbian or otherwise sapphic woman, who has a masculine gender presentation. The term "butch" tends to denote a degree of masculinity beyond what would be considered typical of a tomboy.

Butch women often dress in masculine clothing, and typically present themselves in a more stereotypically masculine way, such as having short hair, not wearing makeup, and not shaving. Butches are also commonly thought of as having more "masculine" interests, such as sports, mechanics, and other hands-on jobs. Some butches will take on masculine names or nicknames, and some may use masculine pronouns. Some butches bind their chest or take masculinizing hormones to appear more masculine. Similarly, transfeminine butches may not take certain steps associated with transfeminine transitioning, such as going on estrogen/anti-androgens. Despite this, butch women are still women. They can be cisgender, transgender or any other gender modality. This label can also be used by non-binary individuals. It is not uncommon for butch women to face harassment or violence because of their appearance.

Butch men are historically associated with biker/leather subcultures, sometimes being referred to as "leather-men." They sought to embody a caricature of hypermasculinity, and subvert the masculinity that heterosexual men displayed. Their relationship with masculinity can be likened to a femme woman's relationship with femininity, though they are not perfectly opposite. In modernity, fewer men attach their butch identity to motorcycle groups and leather, rather focusing on the subversion of typical masculinity in a specifically LGBT+ way.

Traditionally, butches have been expected to be attracted to femmes. For some butches, this attraction to femmes represents a strong part of their own identity. However, some butches are attracted to other butches. This phenomenon is commonly referred to as "masc-for-masc" or "butch-for-butch."

Butch is sometimes used as a non-binary gender on its own, as LGBT+ individuals often have a complex relationship with gender. In a 2015 survey of non-cis individuals in the USA, 5% of respondents (about 1,385 individuals) were butch.

While the butch label is often used by/associated with lesbians, it is also used by other groups in the LGBTQ+ community. This includes m-spec sapphics and LGBT+ men .