English writing skills is a very important part of the English curriculum in primary schools in Kenya. English is taught in primary schools with an aim of enabling learners to acquire writing skills, which in turn enables them to express their own ideas legibly and meaningfully in English and to communicate effectively. Acquiring appropriate English writing skills poses a lot of challenges to learners with Hearing Impairment (HI). This study explored the application of Kenyan Sign Language (KSL) when teaching English writing skills to learners with Hearing Impairment in Special Primary Schools in Kericho County, Kenya. The study was informed by Noam Chomsky’s theory of Universal Grammar of 1977. The study adopted a multiple case study design within a qualitative research approach. The study was carried out in 2 Public Special Primary Schools for the HI in Kericho County. The study population comprised 48 informants (2 Curriculum Support Officers in charge of Special Needs Education drawn from each sub-County where the special school is located; 2 head teachers; 2 Heads of Language Department; 12 teachers of English; 3 parents with HI and 27 learners with HI in class 7). The sample of the study constituted 48 informants (100%) of the population. Purposive sampling was used to sample the two Special Primary schools for the HI while saturated sampling technique was used to sample all the respondents. Data was collected using interview schedules, focus group discussions, observation checklist and document analysis guide. Validity and reliability of qualitative data was ascertained through Lincoln and Guba’s (1985), qualitative paradigm. The qualitative data was analyzed thematically to generate the findings of the study. The findings revealed that teachers of English used Kenyan Sign Language during English lessons which hampered acquisition of English writing skills. Teachers should use Signed Exact English during English lessons.