A systematic review was conducted to identify the relevant theoretical approaches used to explain farmer technology adoption in low- and middle-income countries (LMICS), and their strengths and weaknesses. Scopus and Web of Science databases were searched. 77 articles were finally included. The analysis was based on the following categorization of the theoretical approaches applied: (1) Diffusion theories, (2) User acceptance theories, (3) Decision-making theories, (4) Personality theories, and (5) Organizational structure theories. The analysis indicated that diffusion theories predicted technology adoption but excluded social determinants. User acceptance theories predicted social determinants of adoption intention but not behaviors. Decision-making theories identified measurement variables related to different adoption behaviors, but did not consider influential psychological factors, (implying that only economic factors affected adoption behavior). Personality theories were sometimes complex, resulting in weak predictability of adoption and behaviors. Organizational structure theories emphasized social structure variables but included variables not relevant to the investigation of specific adoption practices. In conclusion, the predictive and explanatory capability of different theoretical approaches depended on the context of agricultural technology adoption.