Conservation Agriculture (CA) is pivotal to achieve sustainable intensification, yet the global efficacy of its core practice, conservation tillage (CT), remains debated regarding the trade-offs between crop productivity and ecosystem services across diverse environmental contexts. Here, we conducted a second-order meta-analysis, synthesizing 69 published meta-analyses, to elucidate the context-dependent drivers regulating the "win-win" outcomes of CT. Globally, CT reduced greenhouse gas (GHG) emissions by 5%, increased soil organic carbon sequestration by 21%, increased soil fertility by 11%, and reduced soil erosion by 12%, all while maintaining crop yields comparable to conventional tillage. However, CT can also emerge as a partial trade-off between crop yields and ecosystem services, notably between crop yield and GHG mitigation. These trade-offs were strongly regulated by climatic and edaphic conditions as well as management intensity. For instance, strong synergies between crop productivity and multiple ecosystem services were more pronounced in (semi-)arid regions characterized by low temperatures and low precipitation, as well as in coarse-textured alkaline soils. Furthermore, integrating CT with residue retention and crop rotations maximized these synergies, mitigating potential yield penalties. Collectively, our synthesis demonstrates that context-specific refinement of CT implementation is essential to reconcile agricultural productivity with ecosystem services, thereby advancing climate-resilient agricultural systems globally.