Orthographic neighborhood size (N size) effect in Chinese character naming has been studied in adults. In the present study, we aimed to explore the developmental characteristics of Chinese N size effect. One hundred and seventeen students (40 from the 3rd grade with mean age of 9 years; 40 from the 5th grade with mean age of 11 years; 37 from the 7th grade with mean age of 13 years) were recruited in the study. A naming task of Chinese characters was adopted to elucidate Nsize- effect development. Reaction times and error rates were recorded. Results showed that children in the 3rd grade named characters from large neighborhoods faster than named those from small neighborhoods, revealing a facilitatory N size effect; the 5th graders showed null N size effect; while the 7th graders showed an inhibitory N size effect, with longer reaction times for the characters from large neighborhoods than for those from small neighborhoods. The change from facilitation to inhibition of neighborhood)