In today’s rapidly advancing world, plastic pollution is increasing at an alarming rate. Plastic materials and their various forms, such as microplastics and microfibers, pose significant issues, leading to the degradation of ecosystems and life on Earth. This has led to the innovation of various sustainable practices that aim to promote environmental conservation and an eco-friendly lifestyle. Mycelium, a network of hyphae, has existed for over a million years but has only recently been recognized for its versatility in innovative and sustainable applications. Mycelium, the vegetative structure of fungi, has garnered attention, especially in the fields of sustainability and eco-friendly materials design. It has revolutionized the fields of fashion and textiles, due to its highly sustainable nature, whereas its biodegradability makes it an excellent alternative to synthetic materials. It exhibits a combination of technical properties, including customization, durability, strength, thermal insulation, and fire resistance, making it suitable for a wide range of domestic and industrial uses. This chapter delves into the science behind mycelium growth, various methods of cultivation, and diverse applications. Through various studies, this chapter highlights the emerging applications of mycelium-based products and their future prospects in addressing the growing sustainability and circularity challenges.