This study aims to understand and assess the diffusion and adoption of RES forenhanced societal wellbeing in developing countries. Furthermore, the purpose is tocontribute to a deeper understanding of the drivers and barriers (D&B) to the diffusionand adoption of RES among smallholders in rural Tanzania. The study onlyinvestigated solar energy lamps and not all products within the scope of RE. This wasto draw a more accurate and relevant conclusion from the empirical study. The study took place in Handeni, Tanzania, from March to May 2022. The primarydata for the study was collected through observations and twenty semi-structuredinterviews in four different villages in Handeni's Rural district. The data sets wereanalyzed through a thematic analysis to identify which D&B the smallholders werefacing regarding the adoption of solar energy lamps. These D&B were later furtheranalyzed with the help of the secondary data from literature studies, where theDiffusion of innovations theory and the Sustainable livelihoods approach were themain theories used. Barriers to adopting solar energy lamps were identified as; knowledge, trust, economy,and accessibility. Driving forces for wanting a solar energy lamp were; the reduced riskof health problems, reduced risk for accidents, portability, facilitating householdactivities, no variable costs, and the possibility to study and work at night. Otherfindings were the need for payment plans, charging on cloudy days, and batteriesthrown in nature. By connecting the drivers with elements from DOI, it was concluded that adoptiononly occurred in households where the driving forces were stronger than the barriers.Furthermore, an assessment of smallholders' wellbeing through the five capitals ofSLA discovered that financial, human, and physical capital were considered low in thestudied area. By bridging the gap between barriers and end-user, an increased diffusionand adoption of RES could occur, raising the capital assets identified as low. This risein the smallholders' low capital assets could push the transformation towardsustainability and enhance societal wellbeing in developing countries. The contribution from this study can hopefully be used for future research on howorganizations in practice can implement presented solutions. Furthermore, the study'sfindings can also provide guidelines on how the diffusion and adoption of RES can beincreased in rural areas of other developing countries. / Minor field studies