The sustainable production and use of small-scale biogas energy is needed to ensure clean household energy access in developing countries including the Sub-Saharan Africa (SSA) region. This is influenced by market risks which can be identified as political, economic, social, technical, legal and environmental (PESTLE). This study examines peer-reviewed and grey literature for the period from 2000 to 2020 to identify the PESTLE constraints and assess their impact on the sustainable deployment of the technology in the SSA region. The production of biogas with small-scale plants is commonly by rural and peri-urban households. Results show that economic constraints are the most dominant and reducing at a slow pace. This is followed by political constraints which have received much attention in the last two decades. Despite the provided policy improvements, national bioenergy policies and interventions are still to make significant gains, especially in the Central African region. In order of significance, the Southern, East and West Africa regions have made comparably larger progress in reducing the constraints. However, to achieve sustainable development of the technology, there is need to further address the PESTLE constraints at national and regional level. This study partly deduces that the unsustainable production, use and inadequate regulation of the small-scale biogas sector is delaying its transition in the SSA region.