Research spanning 20 years is reviewed as it relates to the measurement of cognitive engagement using self-report scales. The author's research program is at the forefront of the review, although the review is couched within the broader context of the research on motivation and cognitive engagement that began in the early 1990s. The theoretical origins of self-report instruments are examined, along with the early measurement findings and struggles. Research in science, technology, engineering, and mathematics contexts are highlighted. The author concludes that self-report data have made significant and important contributions to the understanding of motivation and cognitive engagement. However, the evidence also suggests a need to develop and use multiple approaches to measuring engagement in academic work rather than rely only on self-report instruments. Some alternatives to self-report measures are suggested here and throughout this issue.