Femboy, also spelled femboi, is a slang term for a male or non-binary individual who expresses themselves with traditionally feminine behaviours. As an internet aesthetic, this may be through the use of jewellery, wearing feminine clothing and makeup, or expressing feminine behavioural qualities. Femboy can be used as both a sexual and non-sexual term; it does not denote a specific sexual orientation or gender role, but instead marks a form of gender variance.

The term originated in the 1990s. It has since been popularised through internet forums and social media like TikTok, where trends such as "#femboyfriday" have received attention. In gender studies, the term has been used as an identifier for transgender individuals; in porn studies, the term has been seen as an identifier for a submissive role in intercourse, and as exhibiting elements of sexual fantasy.