Previous studies explored various predictors of network size by examining their effects on mean network size. However, such predictors may not affect the entire distribution of network size uniformly. In the present study, I theoretically predict that extroversion and neuroticism affect the right side of the network size distribution to a greater extent than the left side and test these predictions using quantile regression analysis. The results showed that the effects of extroversion on the size of the inner and outer layers of personal network were significantly greater when the prediction target was the third quartile than when it was the first quartile. The results also showed that although the effects of neuroticism on the inner layer size were significant, that on the outer layer size were not. When the target variable was inner layer size, the relationship between neuroticism and inner layer size was stronger when the prediction target was the third quartile than when it was the first quartile. (C) 2015 Elsevier B.V. All rights reserved.