A parking assistance system for a vehicle includes: an object detection apparatus; at least one processor; and a computer-readable medium having stored thereon instructions that, when executed by the at least one processor, cause the at least one processor to perform operations that include: generating, through the object detection apparatus, information regarding an object located outside the vehicle; determining, based on the information regarding the object located outside the vehicle, that a parking space available outside the vehicle is a diagonal parking space; and generating a diagonal parking path for the vehicle to enter the parking space available outside the vehicle.