The ability to repair and regenerate damaged tissues and/or organs after illness, injury, or aging is vital for the survival of any living organism. The molecular and cellular mechanisms of tissue regeneration have been studied using a variety of animal models, ranging from invertebrates to vertebrates. The findings are serving as the foundation for developing new clinical interventions that enhance people’s ability to heal and regenerate. Recent findings have given us a basic understanding of the molecular mechanisms underlying effective and flawless tissue regeneration and repair, which is summarized in this chapter. Briefly, we describe the molecular mechanisms involved in this regeneration process, including inflammatory responses, regeneration in various organisms, and signaling pathways that may extend our current knowledge to enable the development of novel potential therapies.