Most people agree that young children benefit academically from attending kindergarten; however, some research suggests that any academic advantage attributed to attending full day kindergarten compared to half-day programs will disappear as early as third grade. Based on the results of this study which looked at students in typical classroom settings, a likely explanation for this is that teachers often provide considerable remedial assistance to low achieving students. Once students meet benchmark expectations, instruction tends to broaden to other instructional objectives. We also found that in practice distinguishing between full- and half-day programs based solely on time in school is problematic. Many schools offering full-day kindergarten do not provide a full day of academic instruction, and many teachers see little value of doing so. (Contains 1 table and 2 figures.)