Contra Costa County jurors convicted Marcelles Peter, 20, and Jose Montano, 22, of forcible rape, sexual penetration and forced oral copulation.
Both men could receive life sentences in prison stemming from the October 2009 assault outside Richmond High School's homecoming dance, which drew national attention.
Peter and Montano are among six men accused of raping the victim. Authorities said the girl — a sophomore at the time of the attack— was beaten, robbed and sexually abused over two hours while as many as 20 people watched without reporting the crime, causing intense community scrutiny.
Authorities say incident began when the girl, who was waiting for her father to pick her up from the dance, started drinking alcohol with several young men outside. It quickly turned into an attack in which numerous men raped and beat the girl before running away when police arrived.
Officers discovered the heavily intoxicated girl partially nude and unconscious under a picnic table. She had been suffering from a near-fatal blood alcohol level and head trauma.
"My head really hurt, and I saw five of everybody staring at me," the victim testified last month about waking up in the hospital after the assault. "I felt very nauseous, as if someone had taken out my insides and stabbed them and put them back in."
In the nearly four years since the assault, the victim said she still has shoulder and hip problems from the attack. She also said she now suffers from migraines regularly and has trouble learning.
In 2010, the victim received $4 million to settle a lawsuit against the West Contra Costa Unified School District.
For the past six weeks, two juries heard from about 30 witnesses, including two men, Ari Morales and Manuel Ortega, who took plea deals for their roles in the gang rape and are serving 27-year and 32-year prison terms, respectively.
Peter's jury deliberated for about seven hours before reaching a verdict on Tuesday. Montano's jury deliberated for about 11 hours on Wednesday.
Two other men, John Crane and Elvis Torrentes, are awaiting trial on lesser sexual assault charges.