We evaluated the effects of student characteristics (sight word reading efficiency, phonological decoding, verbal knowledge, level of reading ability, grade, gender) and text features (passage difficulty, length, genre, and language and discourse attributes) on the oral reading fluency of a sample of middle-school students in Grades 6-8 (N = 1,794). Students who were struggling (n = 704) and typically developing readers (n = 1,028) were randomly assigned to read five 1-min passages from each of 5 Lexile bands (within student range of 550 Lexiles). A series of multilevel analyses showed that student and text characteristics contributed uniquely to oral reading fluency rates. Student characteristics involving sight word reading efficiency and level of decoding ability accounted for more variability than reader type and verbal knowledge, with small, but statistically significant effects of grade and gender. The most significant text feature was passage difficulty level. Interactions involving student text characteristics, especially attributes involving overall ability level and difficulty of the text, were also apparent. These results support views of the development of oral reading fluency that involve interactions of student and text characteristics and highlight the importance of scaling for passage difficulty level in assessing individual differences in oral reading fluency.