This study presents a Sliding mode control (SMC) strategy applied to a single-phase grid connected photovoltaic plant. The proposed controller is designed in such a way to control the DC voltage, active and reactive power smoothly, and with insensitivity to system parameter variations and external perturbations. The global asymptotic stability of the developed control laws is guaranteed employing Lyapunov stability theory. So as to verify the effectiveness of the proposed controller, a simulation based comparative study has been carried out under a change in solar irradiance and ambient temperature. The results demonstrate that the SMC provides better dynamic performance, great decoupling of active and reactive power, good reference tracking and improved power quality even when facing operating point variation comparing with the conventional linear controller.