Using hierarchical linear modeling and longitudinal data from the first 6 waves of the Early Childhood Longitudinal Study-Kindergarten cohort, the authors examined reading achievement and growth rates by learning disability (LD) subgroup. The 2-level (time-student) growth curve model indicated that lower levels of reading achievement were already evident at kindergarten entry for all subgroups of students identified during the elementary school years as having LD. Results indicated that students with LD made smaller gains in reading achievement than students without disabilities. This finding underscores the need for frequent, multifaceted assessment of progress and responsive, targeted instruction in addition to early identification. (Contains 1 figure and 3 tables.)