A method for determining a radio resource control (RRC) configuration in a wireless communication system supporting dual connectivity, and an apparatus supporting the same is disclosed. The method for determining, by a base station (BS), a radio resource control (RRC) configuration in a wireless communication system supporting dual connectivity, includes transmitting, by a first BS, a first RRC configuration of a serving cell of the first BS or remained user equipment (UE) capability to a second BS configured in a UE, and receiving, by the first BS, a second RRC configuration of a serving cell of the second BS configured in the UE from the second BS. The first BS and the second BS are involved in dual connectivity for the UE, and the second RRC configuration is determined by the second BS based on the first RRC configuration or the remained UE capability.