The necessity of having energy efficient wireless communication networks emerges because of the related environmental and economical benefits. Achieving energy efficient wireless communications using visible light communications (VLC) has been recently studied due to its transmission properties. Moreover, the integration of VLC and radio frequency (RF)-based wireless networks has shown improved data rate and reliability for the mobile users. In this chapter, we investigate the energy efficiency of the integration of VLC and RF wireless networks. We formulate and solve the energy efficiency maximization problem by allocating the power and bandwidth of a heterogenous RF/VLC wireless network. We study the impact of various system parameters on the network performance. Numerical results are presented to demonstrate the performance gains of the hybrid system and to quantify the impact of the system specifications on the achieved energy efficiency. Moreover, several challenging issues due to the RF/VLC integration are addressed.