Orphan crops can contribute to building resilience of marginal cropping systems as a climate chnage adaptation strategy. Orphan crops play an important role in global food and nutrition security, and may have potential to contribute to sustainable food systems under climate change. Owing to reports of their potential under water scarcity, there is an argument to promote them to sustainably address challenges such as increasing drought and water scarcity, food and nutrition insecurity, environmental degradation, and employment creation under climate change. We conducted a scoping review using online databases to identify the prospects of orphan crops to contribute to (1) sustainable and healthy food systems, (2) genetic resources for future crop improvement, and (3) improving agricultural sustainability under climate change. The review found that, as a product of generations of landrace agriculture, several orphan crops are nutritious, resilient, and adapted to niche marginal agricultural environments. Including such orphan crops in the existing monocultural cropping systems could support more sustainable, nutritious, and diverse food systems in marginalised agricultural environments. Orphan crops also represent a broad gene pool for future crop improvement. The reduction in arable land due to climate change offers opportunities to expand the area under their production. Their suitability to marginal niche and low-input environments offers opportunities for low greenhouse gas (GHG) emissions from an agro-ecosystems, production, and processing perspective. This, together with their status as a sub-set of agro-biodiversity, offers opportunities to address socio-economic and environmental challenges under climate change. With research and development, and policy to support them, orphan crops could play an important role in climate-change adaptation, especially in the global south.