This article reviews research examining technical features of curriculum-based measurement (CBM) in written expression. Twenty-eight technical reports and published articles are included in this review. Studies examining the development and technical adequacy of measures of written expression are summarized, beginning with research conducted at the Institute for Research on Learning Disabilities at the University of Minnesota and followed by extensions of this work. Differences in technical features of writing tasks, sample durations, and scoring procedures employed within and across elementary and secondary levels are highlighted. Gaps in research addressing the technical adequacy of CBM in written expression are identified, and implications for future research and practice are discussed.