In this paper, we propose a fairness-aware energy-efficient power control scheme for device-to-device communications underlaying cellular networks, where multiple D2D pairs reuse the same subchannels allocated to one cellular user. Taking the maximum allowed transmit power and the minimum data rate requirement into accounts, we formulate the fairness-aware energy-efficient power control problem as a generalized fractional programming (GFP) problem, and then develop a two-loop iterative algorithm to solve it. In the outer loop, we resort to generalized Dinkelbach method to equivalently transform the GFP problem into a series of parametric subtractive-form problems, and in the inner loop we combine successive convex approximation and geometric programming to solve the parametric subtractive-form problems to obtain the solutions satisfying the Karush-Kuhn-Tucker conditions. Simulation results are presented to demonstrate the effectiveness of the proposed scheme.