The present study investigated whether morphological processing in reading is influenced by the orthographic consistency of a language or its morphological complexity. Developing readers in Grade 3 and skilled adult readers participated in a reading aloud task in four alphabetic orthographies (English, French, German, Italian), which differ in terms of both orthographic consistency and morphological complexity. English is the least consistent, in terms of its spelling-to-sound relationships, as well as the most morphologically sparse, compared to the other three. Two opposing hypotheses were formulated. If orthographic consistency modulated the use of morphology in reading, readers of English should show more robust morphological processing than readers of the other three languages, because morphological units increase the reliability of spelling-to-sound mappings in the English language. In contrast, if the use of morphology in reading depended on the morphological complexity of a language, readers of French, German, and Italian should process morphological units in printed letter strings more efficiently than readers of English. Both developing and skilled readers of English showed greater morphological processing than readers of the other three languages. These results support the idea that the orthographic consistency of a language, rather than its morphological complexity, influences the extent to which morphology is used during reading. We explain our findings within the remit of extant theories of reading acquisition and outline their theoretical and educational implications.