The 4th International Conference on Mobile Computing and Sustainable Informatics (ICMCSI 2023) organized by Pulchowk Campus, Institute of Engineering, Tribhuvan University, Nepal on 11-12, January 2023 has significantly contributed to address the unprecedented research advances in the areas of mobile computing and sustainable informatics. ICMCSI 2023 is dedicated to explore the cutting-edge applications of mobile computing and sustainable informatics to enhance the future of mobile applications. This international conference serves a forum for researchers to address mobile networks, computing models, algorithms, sustainable models, and advanced informatics that supports the symbiosis of mobile computing and sustainable informatics. The conference covers almost all the areas of mobile networks, computing and informatics.