Integrating literacy and computational thinking (CT) can broaden computer science education participation, especially for multilingual learners. This study examined how ELA-integrated Scratch-based CT curriculum impacts coding attitudes among elementary students in predominantly Latine and multilingual districts. The curriculum integrates literacy strategies into CT instruction as proposed by the National Academies of Sciences, Engineering, and Medicine (NASEM) to support multilingual learners. We conducted a cluster randomized controlled trial with 1,325 students in grades 3–5 across 23 schools in two suburban districts. The treatment group used an ELA-integrated CT curriculum for a school year while controls continued with business-as instruction. Pre- and post-surveys measured five coding attitude constructs: confidence, interest, utility, perceived coding values of social circles, and perceptions of young coders. We estimated treatment effects using a two-level hierarchical linear model, controlling for student and classroom characteristics. Findings show no statistically significant differences emerged in overall coding attitudes between groups. However, students exposed to a year of ELA-integrated CT curriculum showed significant increases in coding confidence. The curriculum did not significantly affect other attitude dimensions. Findings suggest that an ELA-integrated CT curriculum can enhance coding confidence among elementary students, demonstrating the value of early computing exposure and integrated approaches.