The dataset contains all raw data and corresponding standard scores used for analyses in the research described by Walda van Weerdenburg, Wijnants, and Bosman (2015). The manuscript addresses executive functions (EF) in children with dyslexia. For a full description of the reading and spelling remediation program, and all measures see the README file. The experiment design was a longitudinal repeated measures design. During four moments of measurement tests were administered in a one-to-one assessment setting. The pretest (T1) took place prior to all interventions, and three follow-up measurements were administered after three (T2), six (T3), and nine (T4) months of reading and spelling remediation. In this document, the process of collecting data is described, followed by an overview and description of variables included in the data set. 14 tests for EF were used to measure EF in children with severe dyslexia before a reading and spelling remediation program in a specialized reading clinic in the Netherlands. At T1, measurements of intelligence, EF, reading and spelling were assessed. At T2 – T3, measurements of reading and spelling were assessed.