Siaya County in Kenya’s Lake Victoria Basin is characterized by a rapidly growing population, high population density, water scarcity, falling food and fisheries production, and environmental degradation. The combined effects of climate change and rapid population growth are increasing food insecurity, environmental degradation, and poverty levels in the county. Siaya County’s Integrated Development Plan (CIDP) identifies population dynamics, environmental degradation, and climate change as key development challenges. These issues need to be linked in county policies and programs to ensure that projects that address them are implemented jointly. Addressing population growth, environmental degradation, and climate change together should be a top priority if Siaya County is to achieve sustainable development. The county government, donors and program implementers should develop policies and implement programs that integrate population dynamics, environment/climate change, and development.