This study evaluated the Science and Literacy Instructional Model aimed at helping primarily Hispanic bilingual/English Learners (ELs) and economically disadvantaged fifth grade students with science achievement as measured by high-stakes standardized science achievement scores. The model combined purposeful planning, innovative academic vocabulary instruction, and a Lesson Design Lab. Difference-in proportions tests were used to determine if students at two school campuses showed positive achievement gains on a state science test. This study found statistically significant results with medium to large effect sizes at both campuses. Findings contribute to much needed research, practice, and policy in the area of effective models to assist both teachers and students in an era of high-stakes testing.