A black VW Golf was travelling along Barnsley Road, towards Cudworth, when it was in collision with a double decker bus.
Two men, aged 18 and 24, who were travelling in the Golf were pronounced dead at the scene.
The bus driver suffered minor injuries.
South Yorkshire Police are appealing for witnesses to the crash, which happened last night at about 10.30pm.
In a statement, the force said: “It is believed that two other vehicles were in the area at the time and left the scene following the collision.
“We would like to speak to anyone who saw the collision, or captured any footage on a dash cam or CCTV.
“Officers are also keen to hear from anyone who saw what happened immediately prior to the collision.
“Please contact 101, quoting incident number 1001 of Sunday 14 April.”