The bus driver lost control of the vehicle after sharply swerving to avoid a tempo, and collided with the oncoming truck, police said.
The Chandigarh Transport Undertaking bus then skidded off the road and came to a stop on a field adjoining the highway.
Sirsa resident Sharad Kumar, who was travelling on the bus, died on the spot, police said.
Fifteen others travelling on the bus sustained injuries.
They were admitted to a nearby hospital, where the condition of some of them was stated to be serious.