This study examines the relationship between systematic direct observation (SDO) of time on task (TOT) and student engagement as measured by a self-report task-specific measure. The research questions guiding the study are (a) what is the relationship between SDO of TOT and a self-report measure of student effort, and (b) what is the relationship between TOT and reading comprehension? An exploratory analysis compares the engagement among three levels of passage difficulty. Small partial correlations are found between TOT and self-reported engagement among 125 third and fourth graders (r = -0.15 and r = 0.30, respectively). Nonsignificant partial correlations between TOT and reading comprehension are also found. Exploratory multivariate analyses of the three variables show significant results for both third and fourth grade, but subsequent univariate analyses find a significant effect only for comprehension. Thus, these data suggest the need for additional research regarding the assessment of TOT with SDO. (Contains 3 tables.)