This study examined the orthographic transparency of Arabic by investigating the contribution of phonological awareness (PA), vocabulary, and Rapid Automatized Naming (RAN) to reading vowelized and unvowelized words. The results from first and second grade children showed that PA contribution was similar in the vowelized and unvowelized orthographies. The RAN contribution was weak and similar in both versions. The vocabulary contribution increased with grade and was slightly higher in the unvowelized than vowelized orthography. Since orthography transparency in Arabic is determined solely by vowelization, these results are discussed in relation to its position on the transparency-depth continuum.