The current study investigated the predictive utility among teacher-rated, observed, and directly assessed behavioral self-regulation skills to academic achievement in preschoolers. Specifically, this study compared how a teacher report, the Child Behavior Rating Scale, an observer report, the Observed Child Engagement Scale, and a direct assessment, the Head-Toes-Knees-Shoulders task, relate to early math and literacy skills. The sample consisted of 247 children from 31 preschool classrooms. Trained research assistants observed a subsample of 104 children. Results indicated significant, positive relationships for teacher-rated and directly assessed behavioral self-regulation for early math and literacy skills. Teacher ratings were the strongest predictors of literacy, and the direct assessment emerged as the strongest predictor of math. Observed behavioral self-regulation was not significantly related to either academic domain. Discussion focuses on domain specificity of behavioral self-regulation assessments and the importance of utilizing multiple measurement tools when assessing behavioral self-regulation and relations to early achievement. [This paper was published in "Early Education and Development," v25 n5 p641-660 2014 (EJ1030908).]