Background <p>Understanding normal development, disease modeling, and regenerative medicine forms the cornerstone of modern biomedical research. Insights into embryonic and postnatal development enable the study of cellular processes critical for tissue and organ formation.</p> Objectives <p>This review aims to summarize recent advancements in developmental biology, disease modeling techniques, and regenerative medicine, emphasizing the integration of these fields to improve therapeutic strategies.</p> Methods <p>A comprehensive literature analysis was conducted focusing on stem cell biology, tissue engineering, organoid technology, and bioengineering approaches relevant to normal development, disease modeling, and regenerative therapies.</p> Results <p>Advances in stem cell technologies, including embryonic and induced pluripotent stem cells, have facilitated transplantation therapies and tissue regeneration. The emergence of 3D multicellular culture systems, such as organoids, enhances disease modeling by more accurately replicating tissue architecture. Bioengineered organ germs represent a promising strategy for functional organ regeneration. However, challenges remain in mimicking the complex in vivo environment and addressing ethical and technical limitations.</p> Conclusions <p>Multicellular and three-dimensional in vitro models represent critical tools for bridging gaps in our understanding of development, disease, and regeneration. Continued interdisciplinary efforts are essential to translate these findings into effective regenerative therapies and precise disease models.</p>