Sub-Saharan Africa faces intersecting challenges of food insecurity, malnutrition and climate variability, exacerbated by the predominance of rainfed agriculture and limited input use. Climate-smart agriculture (CSA) offers a framework to address these issues through increased productivity, enhanced resilience and reduced environmental impact. Underutilised legumes such as Bambara groundnut (Vigna subterranea), tepary bean (Phaseolus acutifolius) and pigeon pea (Cajanus cajan) present untapped opportunities for advancing CSA objectives. This review synthesises current knowledge on their physiological and agronomic traits such as drought tolerance, nitrogen fixation, short growth cycles and seed priming responses that support climate adaptation in dryland systems. Despite their potential, these legumes remain marginal in formal seed systems, research investment and public policy. Key gaps include limited field-based evaluations, underdeveloped seed and market systems and weak institutional support. The review suggests a whole-of-system approach linking research, extension and policy to scale these crops as strategic assets for resilient, inclusive and nutrition-sensitive food systems in sub-Saharan Africa.