A color gang that was started by a group of middle schoolers in Ikebukuro. The gang was famous for its rivalry against the Blue Square color gang.
The Yellow Scarves are a color gang started by Masaomi Kida to combat against the rival color gang the Blue Squares in Ikebukuro. Even though both groups were composed of middle schoolers and older teenagers, no one took the fighting to any extreme. It wasn't until after Masaomi met Saki Mikajima and Izaya Orihara that things began to grow increasingly violent with both sides. Members of the Blue Squares were outnumbering groups of Yellow Scarves and brutally assaulting then. Masaomi turned to Izaya for guidance and advice which paid off in the long run as the information broker became a tactician for the group.
One day though, Saki was kidnapped by the Blue Squares leader Izumii and his cohorts and tortured Saki by breaking her legs, demanding Masaomi arrive to the parking garage where he jumped them fairly recently. Masaomi tried to call Izaya for help but it is shown Izaya purposefully ignored his called, going so far as to laugh as Masaomi's attempts. He makes his way to the garage as another Blue Squares member informs Kyohei Kadota and his group about the kidnapping and jump of Masaomi. Kadota, disgusted by the actions his gang took, immediately leaves to go save Saki. Walker Yumasaki blows up the van with a few molotov cocktails and rescues Saki as Erika Karisawa and Saburo Togusa prepare to take her to the hospital. Kadota notices on the way there how Masaomi froze up just outside the garage.
It was after this event that Masaomi disbanded the Yellow Scarves since Izumii was sent to jail for aggravated assault. However, when the massive meeting of the Dollars took place, the Yellow Scarves began to rise up once again independent of any major group. When the Slasher attacks occured and Anri Sonohara was attacked, Masaomi took the reigns of leader again vowing to get the Slasher and the Dollars, who he believed were working together after hearing reports that the Headless Rider was a Dollar and was seen helping the Slasher escape.
When the truth comes out about how Mikado Ryugamine is the leader of the Dollars and Anri is the mother of the Slashers, he wonders how things got to where they were as Horada, an ex-member of the Blue Squares, takes over the gang with other ex-members of the Squares and vows to kill both Mikado and Masaomi. However, the Dollars are able to stop them. After the attack, the Scarves begin to dissipate with the Dollars taking over Ikebukuro silently.