Individual decision-making is crucial for rural homeowners to adopt solar home systems (SHS). Currently, SHS adoption in South Africa is slow and disappointing. Individuals choose to adopt or reject a SHS at the household level. This decision results from the interplay of several behavioural intentions emanating from underlying beliefs that are deeply entrenched in society. However, little is known about the underlying beliefs shaping rural and unelectrified households' decision to accept or reject this SHS technology in South Africa. Using the Theory of Planned Behaviour, this paper unpacks underlying beliefs that shape SHS adoption in the Vhembe district of South Africa. A mixed-method approach following a sequential exploratory design was followed. The underlying beliefs were first explored using an exploratory survey design followed by a second explanatory survey design. The qualitative data was analysed with Atlas ti 9, while the quantitative data was analysed with IBM SPSS version 28. Thematic Network Analysis and Exploratory Factor Analysis were this 'study's main data analysis techniques. The qualitative phase produced a 32-item questionnaire explaining the prevailing beliefs in the villages. The EFA performed on quantitative data produced a five-factor pattern matrix explaining 71.2% of the total variance, with all the factors having acceptable internal consistency (Cronbach alpha value) above 0.7. Control, behavioural, normative and trust beliefs emerged as the central underlying beliefs shaping SHS adoption in the district. Incorporating the unearthed beliefs that shape SHS adoption in policy formulation is the first step towards formulating sustainable and effective adoption interventions.