With the increasing energy demand and the fast depleting fossil fuel reserves, alternative energy sources are the need of the hour. These sources are abundant in nature, are a cleaner source of energy, and cause a minimal effect on the environment. Among these energy sources, solar energy is extensively studied and implemented due to its many available applications. However, the solar photovoltaic (PV) system’s performance depends on load impedance, irradiance and ambient temperature. Therefore, it is of utmost importance to achieve a higher output power of the system for maximum efficiency. Maximum power point tracking (MPPT) charge controller is used in the process. It preserves the desirable maximum power point of the PV system. In this paper, a sliding mode controller (SMC) based on a gain adaptation law is proposed to achieve MPP irrespective of rapidly varying weather conditions. The proposed adaptive SMC MPPT controller overcomes the problem of oscillation around an operating point which is inherent in earlier existing MPPT techniques. To test the robustness of the SMC, perturbation and observation (P & O) controlling technique is compared with SMC under varying irradiance and temperature change.