This review comprehensively examines the application of medicinal plants in cosmeceutical formulations, focusing on their bioactive compounds and therapeutic mechanisms for skin health. Cosmeceuticals bridge the gap between cosmetics and pharmaceuticals, delivering physiological benefits through biologically active ingredients. Medicinal plants such as Aloe vera, Camellia sinensis, Curcuma longa, and Centella asiatica contain diverse phytochemicals including polyphenols, flavonoids, terpenoids, and alkaloids that exhibit antioxidant, anti-inflammatory, antimicrobial, and anti-aging properties. These bioactive compounds act through multiple molecular pathways, including ROS neutralization, NF-κB inhibition, tyrosinase suppression, and collagen synthesis stimulation. Modern extraction techniques and advanced delivery systems enhance bioavailability and stability of plant-derived actives. Clinical evidence supports the efficacy of botanical cosmeceuticals in photoprotection, wound healing, and skin aging prevention. The integration of traditional botanical knowledge with contemporary scientific validation positions medicinal plants as cornerstone ingredients in evidence-based skincare, offering safe, sustainable, and multifunctional alternatives to synthetic compounds.