This study examined the relationship between scores on "speeded" cognitive and academic tests and the need for the accommodation of extended test time for normally achieving students (NA) and students with learning disabilities (LD). Often, in postsecondary settings the decision to provide the accommodation of extended test time is based largely on the diagnostic test scores in the student's LD documentation. Therefore, the primary purpose of this study was to evaluate the relationship between specific diagnostic tests and the need for the accommodation of extended test time. A secondary purpose was to investigate the relationships and predictive ability of five speeded cognitive tests, three speeded cluster scores, and two measures of timed reading. Correlations and logistic regression analyses were used to assess gain in score performance and predict the need for extended test time. Participants included 41 NA university students and 43 university students with LD. The findings indicated significant group differences on all speeded cognitive, reading, and academic tests, with the exception of Digit Symbol on the Wechsler Adult Intelligence Scale-III and Retrieval Fluency and Decision Speed tests on the Woodcock-Johnson III Tests of Cognitive Abilities. The Reading Fluency test and the Academic Fluency cluster of the Woodcock-Johnson Tests of Achievement III were the best predictors of students with LD who needed extended time on the multiple-choice reading comprehension test. (Contains 5 tables.)