Commercially produced organic dyes and their derivatives are widely used in a variety of industries, including textile production, paper, cosmetics, medicines, photography, and petroleum. Such industries produce a significant volume of wastewater effluents containing toxic azo dyes (AD), which causes an inevitable state of extreme contamination and a major risk to human health. Due to increasing environmental concerns and awareness of the harmful effects of synthetic dyes, there is a need for sustainable alternatives. Plant- and algal-based biocolors, derived from natural resources, are emerging as eco-friendly and safe options for various industries. These biocolorants, such as carotenoids, flavonoids, anthocyanins, chlorophyll, and betalain, not only provide vibrant colors but also offer functional benefits, including antimicrobial and antioxidant properties. However, achieving sustainability in natural dyeing processes remains a critical challenge, requiring advancements in extraction techniques, dye stability, and industrial applications. This chapter provides a comprehensive overview of plant- and algal-based biocolors, their sources, characteristics, extraction methods, and industrial applications, and their role in promoting sustainability. Furthermore, it explores the technological and economic considerations required to integrate biocolorants into mainstream industrial practices while addressing the environmental and health-related concerns of synthetic dyes.