The occupants of the car were returning from Rohtang Pass when the tragedy struck, police said.
The accident took place as the driver lost control and the vehicle went off the road and fell into the gorge.
The deceased were identified as Amarjeet (23), Nirmal (35) and Neelam (30), all residents of Hisar in Haryana.
The injured -- identified as Sunil (21) and Surjan (13) -- were admitted to Lady Willingdon Hospital, Manali.