A method and apparatus for managing transmit power for device-to-device communication is provided. According to an embodiment of the invention, a UE uses a component carrier of one cell to engage in D2D communication. In parallel with its D2D communication, the UE uses one or more other component carriers of one or more other cells to engage in cellular communication. The UE configures its D2D transmit power as well as its cellular transmit power so that its total transmit power does not exceed the UEs maximum power limit, and so that the transmit power on a component carrier of a cell does not exceed the maximum power limit for the cell that provides the component carrier.