Direct dyes are a class of synthetic dyes widely used in the textile industry for coloring various fibers, including cotton, rayon, and silk. They are called "direct" dyes because they can be directly applied to the fibers without the need for additional chemicals or mordants to fix the color.

Direct dyes are favored for their simplicity of application, cost-effectiveness, and wide color range. They are usually applied in aqueous solution through processes such as dip dyeing, padding, or spraying. However, they have some limitations, including poor light and wash fastness compared to other types of dyes.