This study investigated how Spanish orthographic code complexities influence learning to spell. Word and pseudoword dictation tests were carried out by 208 first- to fourth-grade students. Items included the following orthographic code complexities: digraph, contextual effect, position effect, letter H, inconsistency, and stress mark. The results revealed effect of grade and type of complexity on spelling performance. The type of complexity also interacted with grade and lexical value of the type of items (word vs. pseudoword). It seems that children acquire spelling skills early in terms of phoneme-grapheme correspondence rules, but lexical knowledge develops more slowly. The importance of lexical knowledge is highlighted, as well as the need of prosodic knowledge for the stress mark. (Contains 3 tables.)