The mishap occurred near Kaudigram as the driver of the SUV carrying seven pilgrims from Andhra Pradesh on way to Gaya from Varanasi lost control and rammed into a stationary truck.
Four passengers were killed on the spot, while one of the three injured died in hospital, Mohania police station in-charge Manoj Kumar said.
The deceased have been identified as Satyanarayan (50), his son Pawan Kumar (25) and his mother Padmavati Devi (70), besides Sriram (55), and Rukmini Devi (50), he said.
The pilgrims hailed from Andhra Pradesh's West Godavari district, the officer added.