Inquiry-based learning methods, coupled with advanced technology, hold promise for closing the science literacy gap for English learners (ELs) and students with learning difficulties (SWLDs). Project ESCOLAR (Etext Supports for Collaborative Online Learning and Academic Reading) created collaborative online learning units for middle school science to meet the needs of ELs, SWLDs, and general education students. In a randomized controlled trial with 1,451 students, 28 teachers implemented one of two online units in their classrooms after completing a Web-based professional development course. Results showed that treatment condition students, including ELs and SWLDs, significantly improved science knowledge compared to controls; ELs' gains indicated a knowledge gap reduction compared to general education students. Findings suggest that quality science curriculum and effective technology practices can help all students learn science and prepare for future global scientific challenges.