Kirigami structures have proven instrumental in unlocking diverse properties from conventional materials. Despite the exploration of various geometric patterns and materials in kirigami design, it is crucial to acknowledge that a single kirigami pattern typically exhibits limited configurations and fixed mechanical properties. To address this limitation and advance the functionality and durability of kirigami materials, we present a novel approach—crafting kirigami with a new type of dynamic polymer that we call growing polymer. The growing polymer, synthesized through ring-opening metathesis polymerization (ROMP) of methyl cyclopent-3-ene-1-carboxylate, possesses the unique ability to dynamically alter its size and mechanical properties. Strategically assembling the growing polymers with passive polymers forms the foundation of the growing kirigami. During the growth process, the kirigami is immersed in a monomer solution, initiating osmotic swelling that absorbs monomers into the growing polymer. Subsequent polymerization and chain exchange reactions integrate new polymers into the original network, resulting in macroscopic growth. This growth process vividly showcases the transformation of the kirigami structure from a flat 2-dimensional (2D) configuration into a dynamic 3-dimensional (3D) structure. Moreover, the compressive mechanical properties of the 3D kirigami can be reprogrammed through the growth process. Remarkably, the growing process can be repeated multiple times, offering on-demand reprogramming of the kirigami structure and mechanical properties. Additionally, the growing polymer exhibits a self-healing capability, effortlessly repairing fractures by rejoining two broken pieces and undergoing self-healing for 2 h, resulting in a self-healing kirigami. The synergy between the growing polymer and kirigami design introduces a transformative platform for creating metamaterials characterized by unprecedented reconfigurability and reprogrammable mechanical properties.