The development and use of solar photovoltaic (PV) technologies worldwide is considered crucial towards fulfilling an increasing global energy demand and mitigating climate change. However, the potential of a solar PV-system is location specific, influenced by the local solar resource, energy demand and cost among other factors. The main aim of this study is to conduct a detailed assessment of the potential of solar PV-systems in residential buildings in Lagos Metropolitan Area, Nigeria. Nigeria has enormous solar energy potential, it is the most populous country in Africa and occupies a significant place in the development of Africa. Yet, it is a county with one of the lowest per capita electricity consumption in the world-at 149 kWh per capita for a population of about 170 million, about 7% of Brazil's and 3% of South Africa's. To achieve this goal, this study employed the survey of 150 residential buildings in three local government areas (LGAs) in Lagos State, Nigeria to obtain electric load data. HOMER Pro was used to size the PV-systems and to determine the levelized cost of electricity (LCOE). The computed energy results of the study for the base case scenario revealed the PV array, lead acid 2 battery and the converter (inverter) of the PV-systems to be in the following range: 0.3 to 76 kW; 2 to 176kWh; and 0.1 to 13.2 kW respectively. Economic analysis revealed a LCOE of the systems in the range of 0.398 USD/kWh to 0.743 USD/kWh. The use of PV-system generated electricity in the dwellings has potential for an annual reduction of greenhouse gas emissions in the range of 31.24 kgCO2eq to 7456.44 kgCO2eq. Clearly, the use of solar PV systems in residential buildings possesses potentials for enabling Nigeria to attain its climate change mitigation targets indicated in her National Determined Contributions (NDCs).