The vast majority of students with learning disabilities at the postsecondary level demonstrate reading decoding, reading fluency, and writing deficits. Identification of valid and reliable psychometric measures for documenting decoding and spelling disabilities at the postsecondary level is critical for determining appropriate accommodations. The purpose of this study was threefold: (a) to examine the relationship between specific Woodcock-Johnson III Cognitive and Achievement clusters (WJ III; Woodcock, McGrew, and Mather, 2001) across populations with and without dyslexia at the postsecondary level; (b) to identify the strongest WJ III cognitive predictors for decoding, spelling, and reading fluency across college students with and without dyslexia; and (c) to discuss the implications of the findings for assessment and accommodation practices for secondary and postsecondary students. A total of 101 college students with documented dyslexia and 100 college students without disabilities participated in the study. Both word knowledge and processing speed were found to significantly influence performance in very different ways. (Contains 7 tables.)