The main objective of this research was to assess the influence of visual processing on Arabic reading accuracy and fluency of word recognition in a deep (unvowelled) version and a shallow (vowelled) version of the Arabic script on typical and dyslexic readers. We tested three groups, typically reading 6th graders, dyslexic 6th graders, and typically reading 4th graders, who were matched on reading levels with the dyslexic group. In addition to phonological decoding, we tested orthographic and morphological abilities, as well as nonlinguistic visual abilities. The results showed that overall, the Dyslexic group performed worse on the tests of phonology and orthography than both groups of typical readers, but better than the younger readers on the test of morphological sensitivity. The Dyslexics also performed equivalently to the younger readers on the nonlinguistic visual tests, and both were worse than the age matched controls. Regression analyses revealed that although phonological decoding is the best predictor of accuracy in reading both words and nonwords, orthographic abilities also contribute significantly to the variance. In addition, orthographic abilities were the best predictor of the speed of reading words and nonwords for all groups. Vowelled script slowed recognition and lowered accuracy for all groups.