The study systemically reviewed empirical studies on the assessment of digital multimodal composition (DMC) and identified key domains and criteria for the assessment of K-12 students’ DMC. Based on the concept of multimodality and universal theoretical assumptions on it (Jewitt, 2014), this study argued that assessment tools of DMC should consider both linguistic and non-linguistic modes, their unique communicative roles, relationships between modes, and social norms and conventions about signs. The multi-step analyses drew 19 distinguishable criteria from 111 criteria presented in 15 relevant studies. The findings section defined new criteria and described how they are related to the a priori domains and the existing criteria. This literature review contributes to the field by providing a comprehensive list of criteria for DMC teaching and assessment. Limitations of the study and suggestions for future studies were also discussed.