Police were called to a large scale disturbance which was sparked after the wake for Dylan Paton.
Hundreds of people had gathered in the street in the Craigneuk area of Wishaw, Lanarkshire, where Dylan lived with his family. Witnesses said mourners fought running battles with officers and damaged force vehicles.
Officers rushed to the scene at around 9.15pm on Monday night and a police helicopter was deployed.
Police Scotland said 20 people aged between 12 and 45 years old had been arrested following the incident and are due to appear in court.
They are still investigating and have appealed for witnesses to come forward. Further arrests are expected in the coming days.
Footage of the incident, which shows youths throwing bottles, has been posted online.
One witness said: "It was absolute chaos. Just after 9 o'clock something kicked off and the police were called to the street."
Dylan collapsed at his home last month and was taken to Wishaw General Hospital.
Family members held a vigil at his bedside but he died the following day. Police said there were no suspicious circumstances.
A Police Scotland spokeswoman said: "We can confirm police were called to a report of a large scale disturbance on Gateside Road, Wishaw.
"Anyone with information is asked to contact police on 101."