This chapter discuss the following question: Is there a difference in the assessment for reading processes between students in public or private middle and high school? To answer these questions, this chapter aims to compare the performance of middle and high school students of public and private schools schools using tests from the Brazilian Adaptation of Reading Processes Assessment Battery -PROLEC-SE-R. The Reading Processes Assessment Battery -PROLEC-SE-R, individual version, was applied to 436 students: 221 from public school and 215 from private school, in the following order: 1) Reading Words, 2) Reading Pseudowords, 3) Grammatical Structures II, 4) Punctuation Marks, 5) Reading Comprehension I, 6) Reading Comprehension II, e 7) Oral Comprehension. A cross-sectional study was performed using descriptive and bivariate analysis. Based on these results, the answer to the initial question is affirmative. Private school students do indeed achieve a higher mean score when compared to public school students in word reading, showing that spelling helps in the reading processes. When knowledge of the use of the word in a sentence, extraction of meaning and its understanding is required, the difficulty of accessing the mental lexicon of the population studied becomes evident.