This review article focuses on the development and application of injectable hydrogels in cartilage and bone tissue engineering. It highlights the advantages of injectable hydrogels, such as their high water content, similarity to the natural extracellular matrix (ECM), porous framework for cell transplantation and proliferation, minimal invasive properties, and ability to match irregular defects. The article discusses the selection of appropriate biomaterials and fabrication methods for preparing novel injectable hydrogels, including natural and synthetic biomaterials like chitosan, collagen, gelatin, alginate, hyaluronic acid, heparin, chondroitin sulfate, and poly(ethylene glycol) (PEG). It also covers various fabrication methods, such as physical and chemical approaches, including enzymatic cross-linking, photo-cross-linking, Schiff base cross-linking, Michael addition-mediated cross-linking, click chemistry, ion-sensitive, pH-sensitive, and temperature-sensitive hydrogels. The biology of cartilage and bone, including the composition and structure of their ECM, is discussed to provide a comprehensive understanding of the tissue engineering process. Finally, the article explores future perspectives for injectable hydrogels in cartilage and bone tissue engineering, emphasizing the need for further research to improve biocompatibility, biodegradability, mechanical properties, and in vivo performance.This review article focuses on the development and application of injectable hydrogels in cartilage and bone tissue engineering. It highlights the advantages of injectable hydrogels, such as their high water content, similarity to the natural extracellular matrix (ECM), porous framework for cell transplantation and proliferation, minimal invasive properties, and ability to match irregular defects. The article discusses the selection of appropriate biomaterials and fabrication methods for preparing novel injectable hydrogels, including natural and synthetic biomaterials like chitosan, collagen, gelatin, alginate, hyaluronic acid, heparin, chondroitin sulfate, and poly(ethylene glycol) (PEG). It also covers various fabrication methods, such as physical and chemical approaches, including enzymatic cross-linking, photo-cross-linking, Schiff base cross-linking, Michael addition-mediated cross-linking, click chemistry, ion-sensitive, pH-sensitive, and temperature-sensitive hydrogels. The biology of cartilage and bone, including the composition and structure of their ECM, is discussed to provide a comprehensive understanding of the tissue engineering process. Finally, the article explores future perspectives for injectable hydrogels in cartilage and bone tissue engineering, emphasizing the need for further research to improve biocompatibility, biodegradability, mechanical properties, and in vivo performance.