Adoption and usage of mobile phones enable information and knowledge flows among value chain players, including farmers, and therefore contribute to improved efficiency. To ensure the successful implementation of MPTs in agriculture, farmers should embrace them. We present a systematic review of determinants, constraints, methods, indicators, and measures of MPT adoption among farmers and a methodological quality assessment of the included studies. Findings from 53 studies showed significant heterogeneity in research. Most studies targeted developing regions in Africa and Asia and only a few in developed countries. Although studies mainly focused on MPT adoption, they varied significantly in the outcome indicators assessed and their measurement. This heterogeneity in the conceptualization and measurement of adoption indicators underscores the need for standardized approaches in future studies. There is also sub-optimal use of established psychological-behavioral theories to underpin MPT adoption.Cross-sectional designs and quantitative approaches dominate the research landscape. Concerning farmers' MPT adoption, key drivers were education, age, gender, perceived ease of use, perceived usefulness, perceived cost, performance and effort expectancy, attitude, skills, and knowledge. Factors such as mobile phone cost, inadequate infrastructure, and language barrier constitute major hurdles constraining farmers' adoption of MPT in developing countries. The generally low quality of the reviewed studies suggests that future studies should invest in transparently providing their study objectives, methods, and interpretation of the findings. This systematic review contributes to a better understanding of farmers' MPT adoption drivers and suggests areas for future research. It provides relevant information to policy-makers, public and private sector agencies, mobile phone companies and app developers, researchers, agricultural extension workers, academicians, and other stakeholders when designing and implementing policies for MPT adoption in agriculture.