ABSTRACTThe Next Generation Science Standards and the Common Core State Standards for English Language Arts and Literacy in Science have ignited interest in developing novel ways to support students' literacy development in science classes. To contribute to these efforts, we developed WordSift, a free web-based vocabulary development tool, that has a series of interactive displays, including a list of the 50 most frequent words in a particular text, Google image results for any combination of those words, definitions and synonyms for particular words from the text, and a context in which particular words appeared in the text. Working collaboratively with middle school science teachers from a large urban district, we tailored this tool to fit the needs of science teachers as well as the ones of teachers of other content areas. Here, we provide the rationale and theoretical framework for developing this tool and use examples to explain how science teachers can use WordSift to create interactive and engaging science and literacy lessons.