The ideal periodontal treatment is regenerating functional periodontal tissues destroyed by severe periodontitis. The tissue engineering triad includes stem cells, biological signals, and cell-seeded scaffold that are considered to be essential for tissue regeneration. Periodontal ligament (PDL) tissue contains a stem cell population, periodontal ligament stem cells (PDLSC), that is derived the neural crest tissue. PDLSC demonstrate high proliferative capacity and multipotency that make them a highly promising stem cell population for use in the regeneration of damaged periodontal tissues.Here, we review the current understanding of the features and functions of PDLSC.