Early childhood professional organizations support teachers as the best assessors of students’ academic, social, emotional, and physical development. This study investigates the predictive nature of teacher ratings of first-grade students’ performance on a standards-based curriculum-embedded performance assessment within the context of a state accountability system. The sample includes 4292 elementary school students cross-classified by 131 first-grade and 137 third-grade schools attended. This study uses extant statewide assessment data for students located in a state in the southeastern part of the United States. Controlling for student and school demographic variables in cross-classified random effects multilevel models, first-grade teacher ratings—as reflected by domain scores on a performance assessment—are found to positively and significantly correlate with students’ third-grade academic achievement.