Outdoor textiles provide protection, comfort, and functionality during various outdoor activities. This chapter explores the importance of functional treatments in enhancing outdoor textiles’ performance to meet consumers’ evolving demands and the challenges of modern lifestyles. Functional treatments such as moisture-wicking, thermoregulation, UV protection, antimicrobial properties, and durable water-repellent (DWR) coatings are crucial for creating high-performance fabrics that offer environmental protection, improved comfort, and enhanced user experience. With advancements in technology, innovative approaches like nanotechnology, smart materials, and sustainable manufacturing practices are transforming traditional textiles into versatile, high-tech solutions. This chapter also addresses the growing consumer interest in quality, functionality, and sustainability in outdoor textile products, examining how these trends shape the industry’s research, design, and production processes. Key mechanisms of functional treatments and their practical applications in outdoor textiles are analyzed, highlighting their role in optimizing comfort, wearability, and performance. The chapter concludes by emphasizing the balance between innovation, sustainability, and accessibility, presenting strategies for developing cutting-edge outdoor textiles that meet environmental, economic, and user-centered demands.