The incident occurred about 2:15 a.m. near the intersection of Broadway and Seventh Street, according to a spokesperson for the Los Angeles Police Department.
Investigators said the stabbings happened after two groups apparently got into a confrontation that escalated into a fight. Video posted online captured the melee.
The suspect used a knife in the attacks, the LAPD said. He was identified only as a man in his 30s.
The six stabbing victims were transported to L.A. County-USC Medical Center, two in critical condition and four in stable condition, police said. All six were later listed in stable condition and were expected to survive.
The circumstances that led to the initial confrontation between the two groups was unknown.