In the context of altered climate regimes and escalating costs of cultivation, the conventional and non-cultivation practices have become economically untenable and unsustainable. This variability/fluctuations highlighting the need of adapting crop diversification strategies to promote sustainable agriculture practices and to maintain climate-resilient agroecosystems. Crop diversification helps to mitigate climate change impacts and supports the development of resilient and stable farming systems. Its underlying principles being systematic crop selection, resource conservation, optimal resource utilization, complementary crop combinations, own flourishing of the year-round planning of crop with various species of resources of surplus, not compromising yield and optimizing yield in resource-deprived drylands and rainfed areas. A systematic review of 134 diversified systems, obtained using a PRISMA guided meta synthesis from 2010 to 2025, shows that such systems produce average yields that are 20-38% better than monocropping and builds soil organic carbon by 9% with a reduction of 25-40% synthetic inputs. These study reveales that diversified systems viz., intercropping and agroforestry reliably boost soil health, increase biodiversity, reduces dependence on chemical inputs and consequently improve climate adaptation capacity along with socio-economic conditions. Crop diversification generally reduces the incidence of pests and disease due to increased poplation of natural enemies which disrupts the pest activity compared to monoculturing which makes more susceptible to pests and diseases. Nevertheless, the effectiveness of the diversification is moderated by regional climatic conditions, policy frameworks and access to markets. Adoption is further hindered by knowledge deficit, infrastructural limitations and lack of risk aversion strategies amongst smallholders. This review addresses these gaps by offering a systematic global assessment of the benefits of diversification and the constraints to adoption, highlighting that the scaling of diversification processes requires context-specific policy incentives, knowledge transfer to farmers and value chain development for non-traditional crops.