A thermal management system for a fuel cell includes: a fuel cell stack; a heater connected with the fuel cell stack in parallel through a coolant channel and configured to heat coolant; a pump circulating the coolant; a bypass valve controlling a flow rate of the coolant to be supplied to the fuel cell stack or the heater; a radiator allowing the coolant to exchange heat with external air; a heat dissipation fan supplying the external air to the radiator; a temperature control valve controlling the flow rate of the coolant flowing through the radiator; a temperature sensor disposed at an outlet of the fuel cell stack or an outlet of the heater; and a controller controlling the heater, the pump, the bypass valve, the heat dissipation fan, or the temperature control valve on the basis of temperature sensed by the temperature sensor.