A radio terminal according to an embodiment includes: a controller configured to set a sidelink gap for executing a sidelink operation at a frequency to which a neighbor cell different from a serving cell belongs; and a transmitter configured to transmit, to the serving cell, a predetermined message for indicating that the radio terminal is not interested in the sidelink operation or a measurement report related to a radio environment of the radio terminal. If the predetermined message or the measurement report is transmitted, the controller autonomously releases the sidelink gap configuration even if a message for releasing the sidelink gap configuration is not received from the serving cell.