Population Health and Environment (PHE) strategies are argued to improve ecosystem and human health by addressing family size and its effects on natural resource use, food security, and reproductive health. This study investigates men’s views on a PHE family planning (FP) programme delivered among the pastoral Samburu tribe in rural northern Kenya. Three focus group discussions and nine semi-structured interviews were conducted with 27 Samburu men. These discussions revealed support for environmentally-sensitised family planning promotion. Men highlighted their dependency on natural resources and challenges faced in providing for large families and maintaining livestock during drought. These practices were said to lead to natural resource exhaustion, environmental degradation, and wildlife dispersal, undermining key economic benefits of environmental and wildlife conservation. Relating family size to the environment is a compelling strategy to improve support for FP among Samburu men. Kenyan policy-makers should consider integrating community-based PHE strategies among underserved pastoral groups living in fragile ecosystems.