The incident happened Friday evening on West End Avenue.
Authorities said the suspect entered the home, found the keys in the kitchen and then drove off with the vehicle.
"The suspect entered the unlocked vehicle and either pressed the garage door opener or the garage door was left open," police wrote in a Facebook post around 8:40 p.m.
The residents did not interact with the suspect and were initially unaware the vehicle had been stolen, according to police.
Anyone with information is asked to call 856-429-3000 or email detectives@haddonfield-nj.gov.