This article provides a comprehensive review of Engineered Cementitious Composites (ECC) over the past decade since their invention in the early 1990s. It emphasizes the importance of micromechanics in materials design and highlights unique characteristics of ECC based on extensive theoretical and experimental research. The article discusses the advantageous use of ECC in structural, repair, and retrofit applications, reflecting on past advances and noting future challenges. ECC is described as a class of ultra-ductile fiber-reinforced cementitious composites developed for large-volume construction applications. The development of ECC has benefited from pioneering research by the IPC group and active participation from various international organizations. The article covers important elements of ECC R&D, from materials design to commercial applications, and explores the advantages of high composite ductility and flexible processing. It also examines the performance of reinforced ECC (R/ECC) elements, including their superior shear capacity, ability to sustain large deformations, and compatibility with steel reinforcement. The article discusses the cost considerations of ECC and its potential benefits in terms of safety, durability, and construction productivity. Finally, it outlines future research directions, including standardized mix design, pre-mix ECC, material performance specifications, and sustainable development.This article provides a comprehensive review of Engineered Cementitious Composites (ECC) over the past decade since their invention in the early 1990s. It emphasizes the importance of micromechanics in materials design and highlights unique characteristics of ECC based on extensive theoretical and experimental research. The article discusses the advantageous use of ECC in structural, repair, and retrofit applications, reflecting on past advances and noting future challenges. ECC is described as a class of ultra-ductile fiber-reinforced cementitious composites developed for large-volume construction applications. The development of ECC has benefited from pioneering research by the IPC group and active participation from various international organizations. The article covers important elements of ECC R&D, from materials design to commercial applications, and explores the advantages of high composite ductility and flexible processing. It also examines the performance of reinforced ECC (R/ECC) elements, including their superior shear capacity, ability to sustain large deformations, and compatibility with steel reinforcement. The article discusses the cost considerations of ECC and its potential benefits in terms of safety, durability, and construction productivity. Finally, it outlines future research directions, including standardized mix design, pre-mix ECC, material performance specifications, and sustainable development.