There is growing evidence that schools are not meeting the needs of emergent bilinguals who are falling behind in both academic language development and content knowledge learning. In response to this concern, this article proposes five research-based guidelines for promoting effective instruction for emergent bilinguals. In order to connect theory to practice, implementation of these guidelines is explored through a descriptive study, within a qualitative paradigm, involving Jessica, a Spanish/English bilingual third-grade teacher. Through a description of her science inquiry unit on water, the authors outline how Jessica's instruction reflected the five guidelines. The analysis of her instruction revealed that Jessica developed a standards-based, challenging and enriching inquiry-based curriculum; had high expectations for all of her students and capitalized on their background knowledge and experiences; used a variety of strategies to foster the development of both language and content; created an environment that valued and supported primary language development; and focused on teaching academic language in both English and Spanish.