Drawing on research-informed principles for primary-grade vocabulary instruction, the authors developed a series of engaging vocabulary units for a first-grade class. The units, focused on the explicit teaching of target words and the efficient highlighting of larger sets of semantically related words, involved five complementary elements: reading aloud, explicit teaching of word meanings, rich discussion, independent extension activities, and informal assessment. These elements were implemented within whole-class, small-group, and independent center structures, worked synergistically to support students' word learning, and promoted active student engagement. The authors describe three of the vocabulary units, present data used to document student learning, and discuss implications from the project for teachers searching for feasible, flexible ways to implement rich vocabulary instruction within densely packed daily schedules.