Digital multimodal composing (DMC) is often framed in terms of the use of digital tools to make meaning through multiple modes such as language, image, sound, and gesture. Yet such a focus can make DMC appear to be a neutral process of assembling semiotic resources, rather than a social practice shaped by unequal relations of power. Composing has long been understood as a process of identity construction, and research on DMC has shown that embedded within its practices are inequalities and ideologies that must be examined if DMC is to give rise to possibilities for agency and transformative practice. To cast a light on these issues, this conceptual article offers a redefinition of DMC and draws on Darvin and Norton’s (2015) model of investment to propose a critical model of DMC . Centering the interconnected dimensions of identity, capital and ideology, this proposed model highlights how learners are positioned and position themselves in DMC processes, how access to material, linguistic, semiotic, cultural, and social resources is unevenly distributed and differentially valued, and how norms, policies, and patterns of control shape the conditions of participation. It asserts DMC as dynamic, recursive, and nonlinear practices that unfold across five interrelated processes: gathering, imagining, integrating, reflecting, and sharing. Mapping identity, capital, and ideology across these processes, the article shows how attention to power can help explain both the constraints that circumscribe DMC and its potential to challenge exclusionary conditions, particularly in language learning contexts. The paper concludes by outlining implications, for educators and researchers, of viewing DMC as a situated, ideological, and power-laden practice.