This article presents findings from an intervention across sixth and seventh grades to teach academic words to middle school students. The goals included investigating a progression of outcomes from word knowledge to comprehension and investigating the processes students use in establishing word meaning. Participants in Year 1 were two sixth-grade reading teachers and 105 students (treatment n = 62; control n = 43) and in Year 2, one seventh-grade reading teacher and 87 students (treatment n = 44; control n = 43) from the same public school. In both years, results favored instructed students in word knowledge, lexical access, and morphological awareness on researcher-designed measures. In Year 2, small advances were also found for comprehension. Transcripts of lessons shed light on processes of developing representations of unfamiliar words.