In recent years, 4D printing technology, as an extension of 3D printing, has revolutionized the field of smart materials by introducing time as the fourth dimension, endowing materials with the ability to dynamically respond to external stimuli. At the same time, metamaterials have emerged as a frontier in materials science due to their artificially designed microstructures, which exhibit unique mechanical, acoustic, or electromagnetic properties not found in natural materials. The integration of these two technologies, i.e., 4D printed metamaterials, not only breaks the boundaries of traditional manufacturing but also offers innovative solutions for aerospace, biomedical engineering, soft robotics, and other fields. This review systematically summarizes the research progress and development trends of 4D printed metamaterials from four aspects: technical foundations, material properties, typical applications, and future challenges, with a focus on clarifying the logical connection between 4D printing technology, smart materials, and metamaterial performance, as well as their practical application value.