Unlike the existing literature that has addressed science education and student diversity separately, this study examined urban elementary school teachers’ perceptions of their knowledge of science content, science teaching practices, and support for language development of English language learners or ELL students simultaneously. Furthermore, unlike the existing literature that has addressed school organization and student diversity separately, this study examined teachers’ perceptions of organizational supports and barriers associated with their classroom practices in science. While teachers’ perceptions may distort their actual teaching practices, their perceptions still need to be taken into account when designing interventions, as teachers are more likely to enact changes when those changes reflect their beliefs. Additionally, while it is not possible to produce a fixed list of recommendations for professional development, understanding current science teaching practices in the context of organizational supports or barriers is important for designing and implementing professional development aimed at promoting reform-oriented practices.