Dissolving microneedles (MNs) represent a breakthrough in transdermal drug delivery, offering painless administration, enhanced bioavailability, and elimination of sharps waste. Composed of biodegradable polymers, these MNs encapsulate drugs and dissolve upon skin insertion, releasing their payload directly into the dermis. This review explores the design, mechanisms, and clinical applications of dissolving MNs, focusing on their role in delivering vaccines, biologics, and small-molecule drugs. Advances in material science and fabrication techniques are also discussed, highlighting their potential for personalized dermatotherapy.