Biopolymers and their composites have been extensively investigated in recent years for multiple applications, especially in environmental, medical, and pharmaceutical fields. Bacterial cellulose (BC) has emerged as a novel biomaterial owing to its nontoxic, high-liquid absorbing and holding capacity, drug-carrying ability, and pollutant absorbing features. Additionally, its web-shaped three-dimensional (3D) structure and hydrogen bonding sites have incited a combination of various nanoparticles, polymers, and other materials with BC in the form of composites. Such BC-based composites have been developed through in-situ, ex-situ, and solution casting methods for targeted applications, such as air and water filters, controlled drug delivery systems, wound dressing materials, and tissue regeneration. This review details the production and development of BCbased composites with different materials and by various methods. It further describes various applications of BC-based composites in the environmental and pharmaceutical sectors, with specific examples from the recent literature. This review could potentially appeal a wide readership in these two emerging fields, where novel and advanced materials for different applications have been developed on a regular basis using BC as the base material.