Using data from the Special Education Elementary Longitudinal Study (SRI International, 2002), this study estimated reading growth trajectories in a nationally representative sample of 3,421 students with disabilities ages 7 to 17 representing 11 federal disability categories. Reading achievement in all disability categories increased with age, but the rate of growth decreased with age. Average reading achievement differed by disability category. Students with speech or visual impairments performed highest; students with multiple disabilities or intellectual disabilities performed lowest. Although growth over time was comparable across disability categories, students with speech or hearing impairments or autism improved more slowly than students with learning disabilities. Gender, racial and ethnic, and socioeconomic differences were observed. Implications for accountability policies are discussed. (Contains 2 figures and 4 tables.)