Expert adult readers process fluent and disfluent fonts differently, at both early perceptual and late higher-order processing stages. This finding has been interpreted as reflecting the more difficult to read disfluent fonts requiring greater neural resources. We aimed to investigate whether neural activity is affected by font disfluency in pre-adolescent readers, and to determine if neural responses are related to reading performance. Thirty-three participants between 8 and 12 years old completed two one-back tasks using letter and word stimuli, where font was manipulated (fluent versus disfluent stimuli), during which electroencephalography was recorded. Event related potentials (ERPs) were calculated relative to non-target stimuli for both tasks. The Woodcock Johnson III Tests of Achievement reading specific tests, and the Castles and Coltheart Test 2 were also collected. Font (fluent versus disfluent stimuli) did not consistently affect neural activity during both the letter and word tasks. Fluent stimuli elicited greater late activity (450–600 ms) than disfluent stimuli during the word task, suggesting easy-to-read fonts may enhance the maintenance of words in visual working memory and facilitate the retrieval of semantic information. However, reading performance was not associated with neural disfluency effects, suggesting that pre-adolescents are still at an early developmental reading period. Font manipulation may be a useful way to track developmental reading trajectories in the brain.