It happened around 8:30 p.m. Saturday on the 4400 block of Lanark Road.
Police said the vehicle the victims were traveling in veered off the road and hit a tree. All three victims were pronounced dead at the scene.
Their names have not been released by police, but DeSales University confirmed that two alumni and a current student died in the crash.
"On behalf of the entire DeSales University community, I share our deepest condolences and prayers for the family and friends of the lives we lost," said University President Father James Greenfield, O.S.F.S.
According to WFMZ, Sean Hanczaryk, a senior, and Nicholas White, a 2020 graduate living in Allentown, were both killed in the crash. Emily Kattner, who was a 2020 graduate, was also killed.
The fourth victim, Brandon Dichiacchio, a senior at the university, remains in critical condition.
The Lehigh County Coroner's Office said the three victims died from blunt force injuries.
The cause of the crash remains under investigation.