A method for and apparatus for controlling transmission power in a wireless communication system is provided. A wireless device checks a duration in which a plurality of radio access technologies (RATs) for uplink resources overlaps, determines whether the transmission power of the UE is greater than a maximum power restriction of the UE in the duration, and controls power of at least one RAT based on priorities of the plurality of RATs so that the transmission power of the UE is under the maximum power restriction of the UE. Thus, dynamic and efficient transmission power is supported.