This study examined the type of growth model that best fit within-year growth in oral reading fluency and between-student differences in growth. Participants were 2,465 students in grades 3-5. Hierarchical linear modeling (HLM) analyses modeled curriculum-based measurement (CBM) oral reading fluency benchmark measures in fall, winter, and spring with grade level and student characteristics (including special education and Limited English Proficiency status) as covariates. Results indicated that a discontinuous growth model fit the data better than a linear growth model, with greater growth in the fall than in the spring. Oral reading fluency growth rates also differed by grade and student characteristics. Implications for school practice and research are discussed.