This document introduces ASTA, the Agrifood Systems Transformation Accelerator, a global programme built on the strategic partnership between FAO and UNIDO that uses value chains as entry points for agrifood systems transformation. It explains why a systems approach is needed to address persistent challenges such as fragmentation, project dependency and narrow impact targeting, and outlines how ASTA applies FAO’s sustainable food value chain (SFVC) approach through partnerships, innovation and blended finance. The publication shows how ASTA works in practice through a five-step process, from value chain selection and analysis to implementation, scaling, impact measurement and global learning. It also highlights ASTA’s partnership-based approach and shows how partners can engage to support locally owned, evidence-based and scalable solutions for more sustainable, resilient and inclusive agrifood systems.