"Sigma Boy" (Russian: "Сигма Бой") is a song by Russian bloggers 11-year-old Betsy and 12-year-old Maria Yankovskaya, released as a single by the record label Rhymes Music [ru] on 4 October 2024. It became viral on TikTok and also charted on Spotify, YouTube, Shazam and iTunes. On Spotify, it topped the Viral 50 Global chart at some point.

Betsy has been recording songs for several years. Notably, her "Simple Dimple Pop It Squish" ("Симпл Димпл Поп Ит Сквиш") was reported to have been popular in Asia. Maria Yankovskaya is a blogger and a regular host at STS Kids, a Russian children's TV channel. On 19 October 2024, Betsy and Maria Yankovskaya received the STS Kids' SuperLikeShow award in the "Super Trend" category. They also performed their song "Sigma Boy" on stage during the award ceremony.

The song was written by Betsy's father, composer Mikhail Chertishchev [ru], in collaboration with rock singer Mukka [ru], most notable for the song "Girl with a Bob Haircut" (Russian: "Девочка с каре").

The chorus goes:
   "Sigma, sigma boy, sigma boy, sigma boy
   Every girl wants to dance with you
   Sigma, sigma boy, sigma boy, sigma boy
   I am so very special that it will take you a year to win me over."

According to Mikhail Chertishchev, who wrote the text, his songs' lyrics come to him spontaneously and don't have a meaning initially. He records them on a dictaphone and later evaluates their "virality". According to his daughter, the song's meaning is as follows: "The idea is that Masha and I are so cool, and the Sigma Boy is trying to win us over, and we are trying to win him over too". She has also explained that "the Sigma Boy is a very self-confident boy who doesn't need anyone. At the same time, all the girls fall in love with him."

The song's success is credited to TikTok's "word-of-mouth". Notably, German TikToker Streichbruder (@simonbth1) started a trend in which he put the song on at full volume in public transport and then performed a backflip. (It was part of a larger trend where bloggers go to a public place and blast silly songs that you would normally be ashamed of listening to in front of other people.) Then the song became popular among Roblox players, with one user using it to make fun of guys with "fluffy" hair.

With its simple lyrics and catchy beat, the song has been described as falling under the definition of "brainrot". The attention of the listeners who don't speak Russian is caught by the words "sigma boy", that make the most of the chorus and whose meaning is clear to everybody. However, some people are not "enthusiastic" about the song. On YouTube, many comments are jokes about how the song is annoying and irritating: "My friend had been paralyzed from the waist down, but upon listening to this track he rose to his feet and walked out of the window" or "I set this song as my wake-up alarm tone, and now I wake up two hours early to make sure the alarm won't go off."

• Alpha and beta male § Sigma male

• "Sigma Boy" (official audio) on YouTube