Coloration of pekk fibers

A process for dyeing and reducing the shrinkage of a fiber of a polyetherketoneketone having the following repeating structural unit ##STR2## where A is m-phenylene, p-phenylene or both m-phenylene and p-phenylene present in different repeating units, comprising treating the fiber for at least about one-half hour at a temperature of about 120.degree. C. to 140.degree. C. in an aqueous bath of a carrier containing a disperse dye, said carrier being selected from the group consisting of diphenyl ether and acetophenone and being present in an amount of at least 40% based on the weight of the fiber to be treated and said dye being present in an amount of at least 0.5% based on the weight of the fiber.