Millions of Solar Home Systems (SHSs) have been progressively installed in rural areas of developing regions, usually in isolated locations that lacked access to electricity, clean water and/or sanitation. Monitoring has been identified as a one of the factors that contribute in rural electrification program success due to these actions increase the system lifetime and reduce the failure of operation of the PV system, improving confident level of the users on the system. This work focuses on the study of the current challenges for the mass scale SHSs monitoring in developing countries, highlighting the weak-nesses and the strengths of the applicable methods available. Monitoring systems applicable to SHSs are reviewed, including conventional dataloggers and the novel attempts that apply new technologies based on open source tools and the Internet of Things (IoT). Sensor distributions applicable to SHS monitoring have been reviewed. Main shortcomings related to conventional monitoring systems such as the elevated cost or the dependency on external hardware have been identified, issues that hinder their application of the mass-scale monitoring. Low-cost IoT-based monitoring systems are reviewed and presented as a potential solution to the mass-scale monitoring of SHSs. (c) 2020 Elsevier Ltd. All rights reserved.