Objective: The purpose of this study was determine if the relationship among working memory, attention, and processing speed differentially contributes to areas of academic achievement. Method: This study incorporated archival data from KIDS, Inc.'s School Neuropsychology Post-Graduate Certification Program. Participants included 955 children ages 6-18 with various clinical diagnoses. The predictor variables comprised children's performance on working memory, attention, and processing speed tasks. The following subtests were used from the Woodcock-Johnson Tests of Cognitive Abilities, 3rd Edition – Normative Update: Auditory Working Memory, Memory for Words, and Retrieval Fluency. The remaining subtests were used from the Wechsler Intelligence Scale for Children – 4th Edition and the Wide Range Assessment of Memory and Learning – 2nd Edition: Symbol Search, Digit Span Backwards, and Finger Windows. The outcome variables comprised children's performance on tasks of academic achievement from the Woodcock-Johnson Tests of Achievement, 3rd Edition – Normative Update. Eleven stepwise regression analyses were computed to determine how much working memory, attention, and processing speed together predicted areas of academic achievement. Results: Results confirmed that four areas of academic achievement were predicted by working memory, attention, and processing speed. All three constructs significantly predicted Reading Fluency (F(3, 946) = 20.408, p < .01, R2 = .061), Writing Fluency (F(4, 945) = 21.624, p < .01, R2 = .084), Letter-Word Identification (F(5, 949) = 9.444, p < .01, R2 = .047), and Applied Problems (F(4, 950) = 18.134, p < .01, R2 = .071). Conclusion: Reading seemed to be directly impacted the most by the relationship among working memory, processing speed, and attention.