This study evaluated the psychometric properties of the Student Engagement Instrument Brief Version (SEI-B) longitudinally across three time points with high school students in the Southeastern United States. Two subsamples of one time point were analyzed to validate the factor structure by exploratory factor analysis (40% of the sample) and confirmatory factor analysis (60% of the sample) revealing a five-factor structure in congruence with the full form of the Student Engagement Instrument (SEI). Longitudinal measurement invariance analyses were performed on each of the five imputed datasets following the suggestions and recommendations of Vandenberg and Lance (2000). The SEI-B demonstrated configural, metric, scalar, and uniqueness invariance with acceptable levels and changes of model fit across all time points and datasets suggesting it may be used as part of a comprehensive progress monitoring effort to predict students that may be at-risk to drop out of school.