English Language Learners (ELLs) is the fastest growing segment of the public school population. Today’s schools face unprecedented challenges in preparing ELLs as they lack instructional supports and fair and valid assessments to support academic learning in classroom settings. This study invokes the principles of design-based research, where both qualitative and quantitative data were triangulated and analyzed to further advance the theory of multimodality and assessment within a sociocultural perspective for linguistically diverse students in two sixth grade classrooms during a unit in photosynthesis. The main research question guiding this study: How do multimodal tasks support science learning in linguistically diverse classrooms? This question leads to three main perspectives, first I examine the two teachers’ perspectives on the use of multimodal tasks, next the students’ perspectives on the use of multimodal tasks and finally using a science and language learning rubric, which I created, I examine student learning in the classrooms based on students’ English learner status and proficiencies in English language arts, science, and vocabulary acquisition and usage. The teachers used some multimodal tasks to communicate ideas and the students created visual diagrams and comic strips to represent their understanding of photosynthesis. Results show the specific scaffolding strategies used by the teachers during the tasks, like analogies, contextualization of vocabulary use, re-representation of ideas through different modes and re-representation of modes in every task were also appropriated by the students. Rubric scoring indicated ELLs had the highest gains in the scores in the visual diagrams, redesignated students had the highest scores in the comic strip and those designated as above proficient in language arts and science had the highest scores in final visual diagram, indicating how ELL status, proficiencies in language arts and science influence the integration of science and language learning. With the advent of Next Generation Science Standards and related assessments, the findings illustrate the importance of aligning the multimodal tasks to learning goals, weaving links amongst the multimodal tasks, modeling the use of representational tasks for ELLs to integrate the understanding of science content and language and assessing students’ learning over time using visual representational tasks.