This thesis explores the viability of learning lessons from the water, sanitation and hygiene (WASH) access sectors to improve practice in the energy sectors of the Global South. Within this, it specifically focusses on lessons that have emerged from the use of market-based approaches. While energy access has been rapidly gaining attention in global development discourse, this focus is relatively recent when considering the dedicated attention given to WASH in the past. With careful consideration by practitioners in the energy sector, the lessons learnt from the rich history in WASH could help prevent repetition of past mistakes and improve practice.In order to explore cross sectoral learning between market-based approaches, this research is structured around four research objectives, the first provides the basis for learning lessons across the sectors. Research Objective 1 (RO1) was to: Assess the similarities, differences and overlaps between the WASH and energy sectors, and where possible, identify areas where the sectors could learn from each other. In addressing RO1, a structured literature review was carried out, based around a framework using the following lenses for comparison: (i) social and security; (ii) governance; (iii) commercial; and (iv) technical. This provided a conceptual foundation for structuring a high-level analysis of the key opportunities and trends within the two sectors. It suggested that energy sector actors should carefully consider more meaningful engagement of stakeholders (lens (i)) as well as alternative governance structures found in the water sector (lens (ii)). It also identified an increased focus on privatisation and a shift away from supply-driven approaches in both sectors (lens (iii)), and suggested that market-based approaches may warrant further exploration.Across these sectors, market-based approaches are becoming increasingly prevalent in small-scale service delivery. However, these approaches are poorly understood, with little research into their characterisation. Understanding market-based approaches from the practitioner perspective is essential in exploring cross-sectoral learning between such approaches. Research Objective 2 (RO2) was to understand the key characteristics of the market-based approach to technology transfer in the WASH and energy sectors in order to better define the market-based approach. RO2 consisted of longitudinal research engaging six expert practitioners in multiple online focus group discussions and semi-structured iii interviews. This research found that while there are common characteristics, the marketbased approach is conceptually broad. Market-based actors may face challenges while striving to establish sustainable Base of the Pyramid initiatives, such as tensions in balancing social and economic aims, and ethical challenges that arise as a result of power imbalances.Research objective 3a integrated learnings from RO1 and RO2 and contextualised the research, by looking at opportunities for cross sectoral lessons learning within market-...