Stan Twitter is a community of Twitter users who post opinions on celebrities, music, TV shows, movies, video games, social media, and other topics. It is known for using particular terminology. Discussions in Stan Twitter spaces often revolve around public figures – primarily those in the entertainment industry. Stan Twitter can also be found to support political views.

The origin of the term stan is often credited to the 2000 song "Stan", about an obsessed fan, by American rapper Eminem featuring British singer Dido. The word itself was added to the Oxford English Dictionary in 2017 with the definition "an overzealous or obsessive fan of a particular celebrity”. The term was originally a noun, but over time evolved and began to be used as a verb as well.

Stan Twitter has been noted by The Atlantic as one of the "tribes" of Twitter. Polygon has described Stan Twitter as "an overarching collection of various fandoms", and additionally as a community that "[signifies] individuals congregated around certain, specific interests ranging from queer identity to K-pop groups, and added that "Stan Twitter is essentially synonymous with fandom twitter."

The Daily Dot wrote that "Stan Twitter is essentially a community of Extremely Online like-minded individuals who discuss their various fandoms and what they 'stan'." Stan Twitter has also been noted for its common overlap with LGBTQ+ Twitter communities. The Guardian noted, for example, that "Gay male culture has always coalesced around female pop stars, from Judy Garland to Lady Gaga and Ariana Grande."

Mat Whitehead of HuffPost described stans as "volcanic", and added that they are "organised, ... dedicated and—at times—completely unhinged." Whitehead went on to describe stans of recording artists, writing "stans aren't just superfans, they're a community of like-minded souls coming together, unified under the banner of wanting to see their chosen celebrity flourish. Friendships are made, bonding over a shared love of an artist, their work, their achievements."

Stan Twitter has been noted for its extremely fanatic culture and behavior. Vanity Fair highlighted American pop singers Ariana Grande and Taylor Swift, as well as the K-pop group BTS as artists who have "extremely fanatic fanbases". Vanity Fair also credited those fanbases and "stan culture and its associated engines" with helping propel the popularity of music videos for those artists.

Stan Twitter has also been highlighted for commonly sharing memes within respective communities and utilizing a particular vernacular and terminology. Online stan accounts are frequently run by impassioned teenagers, who often add a distinct touch to their tweets, in contrast to "anonymous accounts jockeying to be the most official unofficial fan source" that can "take on a corporate monotone on par with many singers' own junket." An artist's fanbase is often attached to a nickname used in the media, and in some cases given by the artists themselves. Some social media accounts focused on delivering film, music, and miscellaneous celebrity news, such as Pop Crave, Pop Base, and Film Updates, have been recognized as relevant outlets and aggregators within these stan communities.

Some outlets have also touched on stans being "toxic" in their fanaticism. The subculture has been noted by the BBC for displaying a trend of "toxic fandom" which includes fans joining to bully or harass others in the name of an artist. Entertainment Weekly quoted Jordan Miller as stating "[Stans] will eat their own"; Miller runs BreatheHeavy.com, "a pop music website that for many years was the premier Britney Spears fansite."