Increasing access to computational ideas and practices is one important reason to integrate computational thinking (CT) in science classrooms. While integrating CT into science classrooms broadens exposure to computing, it may not be enough to ensure equitable participation in the science classroom. Equitable participation is crucial because providing students with an environment in which they are able to fully engage and participate in science and computing practices empowers students to learn and continue pursuing CT and science. To foreground equitable participation in CT-integrated curricula, we undertook a research project in which researchers and teachers examined teacher conceptualizations of equitable participation and how teachers design for equitable participation by modifying a lesson that introduces computational modeling in science. The following research questions guided the study: (1) What are teachers' conceptualizations of equitable participation? (2) How do teachers design for equitable participation through co-design of a CT-integrated unit? Our findings suggest that teachers conceptualized and designed for equitable participation in the context of a CT-integrated curriculum across three primary dimensions: accessibility, inclusion, and relevancy. Our contributions to the field of science teaching and learning are twofold: (1) obtaining an initial understanding of how teachers think about and design for equitable participation is crucial in order to support teachers in their pursuit of creating equitable learning experiences for CT and science learners, and (2) our findings show that we can study teacher conceptualizations and their design choices by examining specific modifications to a CT-integrated science curriculum. Implications are discussed.