This study was concerned with the effectiveness of word processing as a written language intervention for primary‐age deaf children. Subjects were 14 children in two primary school deaf‐unit classes matched in terms of age, gender, and degree of hearing loss. A quasi‐experimental design incorporating multiple‐group baselines with pre‐ and post‐tests enabled all subjects to receive the intervention while maintaining experimental control. Samples of children's written language were collected at the end of each phase in the study. Experienced teachers of deaf children rated five dimensions of the quality of the written language samples, while a speech and language therapist judged other linguistic qualities of the writing. Significant improvements in quality ratings over the course of the study indicated that the word processing intervention had led to improvements in the children's written language skills. These results confirm the effectiveness of word processing as an adjunct to the process writing approach to written language instruction for deaf children.