Agrobiodiversity the variety of crops, livestock, and associated wild species that sustain food systems is declining at an alarming rate worldwide. On-farm conservation is the cultivation and evolutionary management of crop diversity by farmers in their own agroecosystems, has emerged as a critical complement to ex situ conservation. This review synthesises the current state of knowledge on the conceptual foundations, threats, methodological approaches, institutional frameworks, and policy dimensions of on-farm agrobiodiversity conservation. It examines the drivers of genetic erosion, the role of community seed banks, participatory and evolutionary plant breeding, and crop wild relatives in on-farm conservation.