Kenneth Marcks, 35, his brother Chad Fluck, 23, who was driving, and uncle Thomas Fallstich, 46, were identified as the victims. The crash occurred about 10 blocks from the home they shared in Salisbury Township, outside Allentown.
The driver of the second car was hospitalized with injuries that were not believed to be life-threatening.
Speed appeared to play a role in the crash, Allentown police Capt. Glen Dorney said. An accident reconstruction team is trying to determine exactly what happened.
Monday would have been Marcks' 13th wedding anniversary. He had lost his job as a forklift operator but was scheduled to have a job interview Monday, said his wife, Amanda. They have four children ages 6 to 14.
Amanda Marcks said the three men left home to head to a convenience store up the street, a trip they made regularly.
"They were supposed to come right back. But they didn't come back," she told The Express-Times newspaper of Easton.
The three victims lived with seven other family members in the home of Donna Marcks, the brothers' mother. Fluck had been working as a welder but was on leave after getting hurt on the job.
"They were good people who would do anything for anybody," Donna Marcks said. "If somebody needed help, they would be there."