The role writing plays in learning science has evolved over time, as have the settings and contexts in which writing in science research has taken place. This systematic review examines 20 years (1996-2016) of writing in science intervention studies in K-12 settings with a specific focus on comparing contexts that do and do not include English language learners (ELLs), who are at risk academically. Findings include an overall validation of writing-to-learn theories in science learning contexts. Findings also include notable differences between articles containing studies that include ELLs and those that do not such as a general lack of depth in terms of description, analysis, and rigor on writing with ELLs in the science classroom. In addition, trends over the last two decades are noted. Implications for research and practice based on the findings are discussed.