Solar desalination has a significant potential for addressing the increasing water scarcity of the world. Solar stills offer a sustainable solution for desalination of brackish water. Integration of Phase Change Material (PCM) in the still is one of the options for enhancing its productivity. Integration of PCM in solar stills has gained attention due to its capability to efficiently store and release thermal energy thereby enhancing its productivity. The present work proposes a modeling framework for the performance assessment of simple double slope solar stills integrated with PCM. The methodology is based on energy and exergy balance of the overall system. The exergy destruction associated with the still has been evaluated for the basic still and is compared with the case of PCM integrated still. The developed mathematical modeling framework is validated based on comparisons with the experimental observations for the south Indian location of Kozhikode. Lauric acid is considered as the representative PCM due to its favorable thermal properties for the application in solar stills. There is a reasonable agreement between the theoretical and experimental observations. With the incorporation of lauric acid as the PCM in the system, daily yield, daily thermal efficiency and exergy efficiency were found to be increased by 8.9%, 10.6%, and 3% respectively. A generic modelling framework for energy and exergy-based performance assessment of a PCM integrated still has been presented, which will be a useful tool for system optimization. Integration of different PCM with enhanced thermal properties are planned as future work for overall system optimisation for maximum energy efficiency.