This chapter aimed to characterize the performance of students with Attention Deficit Hyperactivity Disorder (ADHD) and to compare that with the performance of students with good academic performance on the reading assessment processes. Methods: Forty students took part in this study. Their ages ranged from 8:2 years old to 10:11 years old, and they belonged to both genders. These students attended from 1st to 4th grades of elementary school. They were divided into two groups: GI - 20 students with interdisciplinary diagnosis of ADHD, and GII - 20 students with good academic performance, paired up with GI according to gender, age and school level. The students were submitted to the application of a Brazilian adaptation of the assessment of the reading processes – PROLEC, composed of four blocks: identification of letters, lexical, syntactic and semantic processes. Results: a statistically significant difference was found between GI and GII in the Prolec tests, with the exception of the same-different and lexical-decision tests, indicating that the students of GI presented lower performance when compared with students of GII. Regarding the classification of the results of Prolec, there was a statistically significant difference in the lexical, syntactic and semantic processes and the letter-sound test, with the exception of the same-different test of the process of letter identification. Conclusion: The findings suggest that the group of students with ADHD shows lower performance compared to the group without problems, highlighting that the attentional factor affects the cognitive functions impairing the acquisition of skills necessary to the learning of reading.