The goal of this study was to assess the relationship between amount of instructional time and student achievement. Two questions were addressed: (a) Do students who have more time allocated to a particular subject area also learn more in that area? and (b) Do students who spend more "engaged time" in a particular subject area learn more in that subject area? Achievement tests in reading and mathematics were administered in nine grade 2 classrooms on two occasions approximately eight weeks apart. In the inter-test period, time allocated to specific content categories was reported daily by teachers. In six of the classes "engaged time" was assessed by direct observation. Quantities of allocated and "engaged time" were related to achievement in a series of regression analyses. Instruction time and student achievement were positively related. Substantial differences in amounts of time were necessary before this relationship could be detected. The strength and consistency of the relationship varied considerably. (Authors)