Police said gunfire broke out around 11:30 p.m. near the courtyard of a building on Quincy Street where a barbecue was being held.
The 8-year-old victim was grazed by a bullet in the leg.
Three other people, a 27-year-old man and two women aged 35 and 46, were all shot in the leg.
All of the victims were treated at Kings County Hospital.
Police said the victims don't appear to be the intended targets and no arrests have been made.
It was the first of four shootings in Brooklyn late Saturday night or early Sunday morning.
About an hour later, a man was shot four times in the chest on Ralph Avenue also in Bedford-Stuyvesant.
He was also taken Kings County Hospital.
An hour after that, an 18-year-old man told police he was standing at the intersection of 3rd Avenue and Warren Street in Boerum Hill when a dark colored sedan and approached and a gunman opened fire.
He was shot in the leg and taken to New York-Presbyterian Brooklyn Methodist Hospital for treatment.
Finally, just before 8 a.m. Sunday a 32-year-old man was shot once in the torso on Wortman Avenue in East New York.
He was being treated at Brookdale Hospital.
MORE NEWS: Brian Laundrie's notebook revealed: 'I ended her life'
Brian Laundrie's notebook revealed: 'I ended her life'
* More Brooklyn news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube
Submit a News Tip