This Chapter addresses the linkages between water and energy systems in Nigeria from the perspectives of socio-economic development, climate variability, and sustainability. Despite the vast resources, Nigeria grapples with a lack of power and clean water on account of decayed infrastructure. Within the framework of water–energy nexus, this review focuses on interconnections identified through the literature between water for energy (e.g. hydropower generation, thermal plant cooling) and energy for water services (irrigation pumps, urban water supply, wastewater treatment). The synthesis reports that the gas-based power-generating plants form 80% of Nigeria’s electricity, whilst hydropower plants constitute only about 20%. By contrast, there is restricted access to clean water and electricity, as only 14% of the population has clean water, with about 45% lacking electricity. The ubiquitous environmental pollution in the Niger Delta, the acute water scarcity of northern Nigeria and fragmented governance inhibiting integrated planning were identified as some of the major sustainability challenges from available literature. This chapter highlights the importance of coordinating investments in data-driven basin management, renewable energy and resilient infrastructure for achieving SDGs 6, 7 and 13. One of the strategic ways for Nigeria to achieve an inclusive growth, climate resilience and long-term resource security is by strengthening the water-energy nexus.