Colour plays a significant role in every aspect of our lives from the clothes we wear and the furniture in our homes to religious rituals and even the food we consume. A chemical compound is perceived as a colour when it absorbs certain wavelengths of visible light while reflecting or transmitting others. Colours are generally classified into four categories: natural colours, nature- identical colours, synthetic colours and inorganic colours. Biocolour refers to a dye or pigment derived from biological sources such as plants, insects, animals or microorganisms. When applied to food, medicines, fabrics or cosmetics, biocolours impart colour through eco-friendly means. Natural colouring agents obtained from plant sources such as chlorophyll, carotenoids, and betacyanins are widely used in medicine, food preservation, textiles and molecular biology, offering environmentally safe alternatives to synthetic dyes. Colours derived from natural sources are collectively termed ‘biocolours’. These are typically extracted from various plant parts, including fruits, vegetables, seeds and roots, and also from microbial sources. Among all sensory attributes, colour is often the most critical factor in food, as it significantly influences consumer perception of quality. This chapter discusses the types, biosynthetic pathways, molecular structures and biochemical properties of various biocolours.