Sigma Boy is a Russian pop song by Betsy and Maria Yankovskaya, released in 2024, whose catchy chorus became a global TikTok sound in late 2024 and early 2025. Short clips of the title phrase spread through sigma edits, dance videos and ironic memes, often detached from the full song. Its simple, repetitive hook and association with online sigma culture helped it stay in circulation long after its initial viral peak, making it a shorthand for exaggerated confidence in short-form video.