A transmission terminal that is configured for executing communication with another transmission terminal at a destination side by communicating with a relay device configured for relaying image data that is communicated among a plurality of the transmission terminals, and configured for communicating with a transmission management system for managing the transmission terminals, the transmission terminal comprising: a transmitter configured to transmit, to the transmission management system, a request for additional display data, as a destination name of the other transmission terminal or a predetermined message; a receiver configured to receive the additional display data that is transmitted from the transmission management system in response to the transmission of said request by the transmitter; and a display control unit configured to attach the received additional display data to data of an image that is transmitted from the other transmission terminal at the destination side through the relay device and that does not show a subject at the destination side, wherein the display control unit causes a display unit to display the data of the image to which the received additional display data is attached; characterized by: a reception unit configured to receive a setting that the destination name is to be displayed or a setting that the predetermined message is to be displayed, wherein the transmitter is further configured to transmit, in the request for the additional display data to the transmission management system, information on whether or not to display the destination name and in a case in which the destination name is not to be displayed the predetermined message received by the reception unit is selected to be displayed. a transmitter configured to transmit, to the transmission management system, a request for additional display data, as a destination name of the other transmission terminal or a predetermined message; a receiver configured to receive the additional display data that is transmitted from the transmission management system in response to the transmission of said request by the transmitter; and a display control unit configured to attach the received additional display data to data of an image that is transmitted from the other transmission terminal at the destination side through the relay device and that does not show a subject at the destination side, wherein the display control unit causes a display unit to display the data of the image to which the received additional display data is attached; characterized by: a reception unit configured to receive a setting that the destination name is to be displayed or a setting that the predetermined message is to be displayed, wherein the transmitter is further configured to transmit, in the request for the additional display data to the transmission management system, information on whether or not to display the destination name and in a case in which the destination name is not to be displayed the predetermined message received by the reception unit is selected to be displayed. a reception unit configured to receive a setting that the destination name is to be displayed or a setting that the predetermined message is to be displayed, wherein the transmitter is further configured to transmit, in the request for the additional display data to the transmission management system, information on whether or not to display the destination name and in a case in which the destination name is not to be displayed the predetermined message received by the reception unit is selected to be displayed.