Spider silk, known for its unique combination of tensile strength, elasticity, toughness, and biocompatibility, is a natural biomaterial produced by different species of spiders from their silk gland. This book chapter deals with the biology and multifaceted potential of spider silk, mainly its ecological and medicinal properties. Spider silk produced through specialized abdominal glands of spiders and extruded through spinnerets is mainly composed of spidroins proteins that form highly organized nano-crystalline structures which are responsible for its mechanical performance. Spiders synthesize various types of silk, each one adopted for its various function ranging from web construction and prey capture to reproduce and mobility. This book chapter also deals with types of spider silk such as dragline, tubuliform, and aciniform types. This chapter gives an overall aspect of spider silk from historical point of view to its use in current scenario in various biological and biomedical fields such as preparation of silk sutures, artificial ligaments, drug delivery system, bone tissue engineering and even cardio-vascular tissue engineering. Apart from this, use of spider silk in high-performance textiles, biodegradable plastics, and eco-friendly adhesive highlights its significance in material science. The chapter concludes with an overview on future challenges in synthetic production, functional customization, and the translation of spider silk into more usable commercial and clinical products. By drawing inspiration from natures design, spider silk exemplifies the promise of biomimetic revolution for justifiable and high-performance technologies.