Abstract. This study tried to replicate and extend the semantic transparency morphological effect using the flanker lexical decision paradigm ( Grainger et al., 2020 ). In the first experiment, stems were used as flankers of target words that could be truly morphological ( hunt hunter hunt), pseudomorphological ( corn corner corn), or form-related with the flanker ( broth brothel broth). In half of the trials, a related flanker was employed, and in the other half, an unrelated word was presented as flanker (e.g., table player table). The results showed a facilitative effect for the related condition as a main effect with no difference between experimental conditions. These results were interpreted in terms of an orthographic facilitation taking place when whole stems are presented as flankers. In the second experiment, short derivational suffixes were used as flankers of the same targets employed in the first experiment. The results showed an inhibitory effect of the same magnitude for the transparent and pseudomorphological conditions with no effect for the form condition. This finding suggests an inhibitory effect by which morphemes activate several lexical candidates that compete for recognition. Overall, the results are interpreted in terms of the cognitive requirements of the experimental task, the items selected, and the current models of morphological processing.