This qualitative study investigated the writing processes of eight emergent bilingual children as they composed stories in two languages in a Writing Workshop (WW) context. The research was situated in two grade 1 classrooms in a Spanish/English Two-Way Bilingual Education program in the north-eastern USA. For six months, researchers observed students in Spanish and English WWs, interviewed students about their writing behaviors and understandings, and collected samples from all stages of the writing process. Cross-case analyses of individual bilingual writing profiles revealed similarities and differences in students’ cross-linguistic skills, as well as patterns of transfer. Patterns of bilingual writing related to strategic codeswitching, positive literacy transfer, and interliteracy led to the development of a preliminary model of bilingual writing development for English-dominant and Spanish-dominant bilingual learners.This model presents phenomena unique to bilingual writers, relates these to bilingualism and biliteracy, and proposes anticipated expression of the phenomena for developing Spanish-dominant and English-dominant bilingual writers.