Digital multimodal composition offers opportunities for emergent bilingual (EB) students to orchestrate semiotic resources in ways that develop their identities, strengthen their understandings of language, and help them to engage with content. To better understand how EBs can participate in varied multimodal composing practices, this study systematically reviews the literature on EBs' digital multimodal composing in secondary classrooms. More specifically, it examines types of scaffolds, or planned and responsive instructional supports, used by teachers and students, as well as functions for learning associated with these scaffolds. Through an inductive approach, the authors analyzed 74 studies situated in classrooms. Findings showed seven types of scaffolding: collaboration, direct instruction, exemplar texts, translanguaging, discussion, encouragement, and questioning. In addition, eight scaffolding functions emerged that illustrate three major themes of scaffolding identities, scaffolding resources, and scaffolding contexts. The authors then discuss implications for classroom practice, implications for translanguaging and social semiotics theories, and directions for future research.