A thermal management system for a vehicle adjusts a temperature of a battery module by using one chiller that performs heat exchange between a refrigerant and a coolant. The thermal management system includes: a cooling apparatus for circulating a coolant in a coolant line to cool an electrical component and an oil cooler provided in the coolant line; a battery cooling apparatus for circulating the coolant to the battery module; a chiller to cause heat exchange between the coolant and a refrigerant to control a temperature of the coolant; a heater that heats an interior of the vehicle using the coolant; and a first branch line connected to the coolant line between the oil cooler and a radiator through a first valve. In particular, a condenser included in the air conditioner is connected to the coolant line so as to pass the coolant circulating through the cooling apparatus.