The pilgrims were returning to their native village of Nirsa in Dhanbad district when the heavy vehicle turned turtle, Deputy Superintendent of Police (Bagodar), Deepak Sharma said.
While two women and a man were killed on the spot, the 22 injured people, two of them seriously, were rushed to nearby hospital in Dumri, Sharma said.
Two of the injured were in critical condition.
Sharma said the helper was driving the bus and probably dozed off.