This chapter presents a review of the related literature on organizational mobile commerce (m-commerce) adoption, leading to the development of an integrated model for evaluating the critical determinants of m-commerce adoption in small and medium-sized enterprises (SMEs) in developing countries. Grounded in the innovation diffusion literature and the extension of the technology-organization-environment framework, the model, integrates technological, organizational, environmental, and managerial factors holistically for better understanding m-commerce adoption in a developing context. Eleven hypotheses are proposed and tested using multiple regression with the data collected from a survey with SMEs' managers in Vietnam. The results confirm the significance of factors in the above four dimensions. These findings provide the managers of SMEs with useful insights on how to improve the adoption of m-commerce in SMEs. These are also useful for policymakers in designing policies that promote the wide adoption of m-commerce in SMEs in the context of developing countries.