Language transfer theory elucidates how first language (L1) knowledge and grammatical features are applied in second language (L2) writing. Deaf and hard of hearing (d/hh) students who use or are developing American Sign Language (ASL) as their L1 may demonstrate the use of ASL linguistic features in their writing of English. In this study, we investigated the extent to which 29 d/hh students in Grades 6-8 (mean age=13.2) with diverse ASL exposure incorporated ASL features in their English writing. We also investigated the impact of one year of Strategic and Interactive Writing Instruction (SIWI) to increase students' metalinguistic knowledge and linguistic competence, and subsequently reduce ASL features in writing. Results indicate that ASL transfer is found in the writings of students with varied L1 experiences, and that SIWI can lead to significant reductions of ASL features in writing. The findings suggest that bilingual literacy programs where there is an emphasis on implicit language competence and metalinguistic knowledge can support d/hh students in the development of written English.