The purpose of this study was to examine (1) the stability of latent classes associated with reading disability (RD) and typical development (TD) across time, (2) the importance of speeded word recognition as a latent class indicator of RD and TD, and (3) possible early indicators of students with late-emerging RD. Analyses were based on a longitudinal sample of 177 students, some of whom had been assigned randomly to small-group tutoring in either fall or spring of 1st grade. At the end of 1st, 2nd, and 4th grades, students were assessed on word identification, sight word efficiency (SWE), and passage comprehension. Latent transition analysis models were developed to examine classification transitions from 1st to 4th grade and 2nd to 4th grade. Results indicated that RD/TD classification was relatively stable across time, however 5 students were consistently identified as having late-emerging RD. Findings indicated that SWE measured in 2nd grade reduced the number of false negatives for RD and was therefore important for the classification of RD. Finally, although students with late-emerging RD had poorer listening comprehension skill at the start of 1st grade and smaller word reading fluency slopes during 1st grade compared to TD children, these indicators did not reliably distinguish students with late-emerging RD from TD due to high rates of false positives. (Contains 3 figures and 4 tables.)