Recent research with adult participants using the flankers task has shown that the recognition of central target words is facilitated by the presence of morphologically related flanker words. Here we explored the development of such morphological flanker effects in two groups of primary school children (average ages = 8 years 6 months and 10 years 3 months) and a group of adult participants. We examined effects of a transparent morphological relation in two conditions: one where the target was the stem and flankers were derivations (e.g., farmer farm farmer) and the other where the flankers were stems and the target was the derived form (e.g., farm farmer farm). Morphological flanker effects were compared with repetition flanker effects with the same set of stimuli (e.g., farm farm farm; farmer farmer farmer), and effects of related flankers were contrasted with the appropriate unrelated flankers. Results revealed no significant effect of morphological relatedness in the two groups of children and a significant effect in the adult group, but only for suffixed targets and stem flankers. Repetition effects for stem targets were found across all groups, whereas repetition effects for suffixed targets were found only in the older children and adults. These results show that morphological processing, in a context involving multiple words presented simultaneously, takes several years to develop and that morphological complexity