Despite the fact that sustainable agricultural technologies and practices have been developed and introduced to farmers in both developed and developing countries, there are concerns about low levels of adoption. Empirical evidence of the past 40 years shows that adoption of new practices can be hindered by a wide range of factors, from financial to attitudinal, from personal to social, from agronomic to regulatory. Conclusions that can be generalised across different contexts could help in moving the institutional and policy environment in a direction that strengthens the move towards a more sustainable food production. This is particularly important regarding hotspots of environmental pollution, for example, the release of reactive nitrogen compounds in South Asia. This paper followed the PRISMA protocol and systematically reviewed the adoption literature in South Asia to identify factors that affect farmers' decisions to adopt sustainable agricultural technologies and practices. We found that education, extension and training, soil quality, irrigation, income and credit are significant drivers of farmers' adoption decisions. Consequently, efforts to promote the adoption of sustainable nitrogen management technologies will have to be tailored to consider these factors. We conclude that the variables that explain adoption in the studies reviewed could provide a foundation invaluable to research and policies that facilitate the adoption of sustainable nitrogen management technologies and practices in South Asia.