A method and apparatus for securing a quality of service (QoS) of data communication is provided. The method of securing the QoS of data being received by a mobile terminal at a reception side that performs a handover from a first network to a second network comprises generating a packet including information about the second network, transmitting the packet to a transmission side, and selectively performing the handover according to whether a packet including information in response to the packet is received. When a reception side performs a handover, a transmission side can be informed of information about the second network via the exchange of packets between the reception side and the transmission side, thereby securing a QoS of the data transmission.