In Internet culture, brain rot (or brainrot) refers to any Internet content deemed to be of low quality or value, or the supposed negative psychological and cognitive effects caused by it. The term also refers to excessive use of digital media, especially short-form entertainment, which may affect cognitive health. The term originated within the online cultures of Generation Alpha and Generation Z, but has since become mainstream.

The term was named Oxford Word of the Year in 2024, beating other words like demure and romantasy. Its modern usage is defined by the Oxford University Press as "the supposed deterioration of a person's mental or intellectual state, especially viewed as the result of overconsumption of material (now particularly online content) considered to be trivial or unchallenging".

According to Oxford University Press, the first recorded use of the term traces back to the 1854 book Walden by Henry David Thoreau. Thoreau was criticizing what he saw as a decline in intellectual standards, with complex ideas being less highly regarded, and compared this to the 1840s "potato rot" in Europe.

In online settings, it was used as early as 2004. In 2007, the term "brain rot" was used by Twitter users to describe dating game shows, video games and "hanging out online". Usage of the phrase increased online in the 2010s before becoming rapidly more popular in 2023, when it became an internet meme. In 2024, it is most frequently used in the context of Generation Alpha's digital habits, by critics expressing that the generation is "excessively immersed in online culture". It is commonly associated with an individual's vocabulary consisting exclusively of internet references. From 2023 to 2024, the term increased by 230% in frequency per million words.

The term is often linked with slang and trends popular among Generation Alpha and Generation Z, such as "skibidi" (a reference to the YouTube shorts series Skibidi Toilet), "rizz" (charm), "gyatt" (referring to the buttocks), "fanum tax" (stealing food), "sigma" (referring to a leader or alpha male), and "delulu" (truncation of delusional). Some online content are commonly labelled "brainrot", such as the web series Skibidi Toilet. Other examples of popular brain rot are memes such as the TikTok Rizz Party and Quandale Dingle, which utilise the slang mentioned above.

In 2024, millennial Australian senator Fatima Payman made headlines by making a short speech to the Australian parliament using Generation Alpha slang. She introduced the speech as addressing "an oft-forgotten section of our society", referring to Generations Z and Alpha, and said that she would "render the remainder of my statement using language they're familiar with". Using slang terms, Payman criticised the government's plans to ban under-14s from social media and closed by saying that, "Though some of you cannot yet vote, I hope that, when you do, it will be in a more goated Australia for a government with more aura. Skibidi!" The speech, written by a 21-year-old staff member, was labeled by some as an example of "brainrot" outside the online world.

• Digital media use and mental health
• Enshittification – Systematic decline in online platform quality
• Glossary of Generation Z slang
• Low culture – Term for forms of popular culture with mass appeal
• Shitposting – Intentionally posting poor-quality social media posts
• Sludge content – Genre of split-screen video on TikTok
• Slop (artificial intelligence) – Low quality AI-generated contentPages displaying short descriptions of redirect targets