Organoids are a groundbreaking advancement in biomedical research, representing miniaturized and simplified versions of organs produced in vitro. They are derived from stem cells—either embryonic, induced pluripotent, or adult stem cells—and can self organize into three-dimensional structures that closely mimic the complexity of actual human organs. Organoids can replicate key organ function and architecture aspects, making them invaluable tools for studying organ development, disease modeling, drug testing, and personalized medicine. Their use spans various organ systems, including the brain, gut, liver, and more. Organoids offer a more ethically sound and biologically relevant alternative to animal models, providing deeper insights into human biology and disease and opening new avenues for regenerative medicine and transplantation research.