We examined the contribution of semantic similarity to morphological priming effects, using the immediate (Exp. 1 and 3) and the delayed variant (Exp. 2) of picture–word interference. Distractor words were either compounds morphologically related to the picture name, but differing with respect to their semantic transparency (hummingbird, jailbird (Exp. 1); butterfly, butter dish (Exp. 3)), or form-related non-compound words (e.g., trombone). All three experiments revealed strong facilitation of picture naming due to morphologically related distractors. Form-related distractors facilitated picture naming in the immediate variant only, and to a lesser degree than compounds. Interestingly, the size of the morphemic effect was almost identical for semantically transparent and opaque complex words, which suggests that they share morphemic representations. These results suggest that morphological complexity in speech production is coded at the level of form representations, independent of semantic transparency.