Bicycling is associated with a variety of personal and societal benefits and it is an important political agenda to increase the number of bicyclists on the roads. However, bicyclists are vulnerable to aggressive traffic behavior and harassment from drivers, and bicyclists' safety concerns stand out as a barrier against increased bicycling. Even so, research on mechanisms underlying drivers' behavior toward bicyclists is scarce. The present study aimed at exploring the relationship between personality and driving behavior. In a sample of 1196 Norwegian drivers, the present study examined the direct, indirect and moderating effects of drivers' extraversion and neuroticism on their aggressive and considerate behavior toward bicyclists. Results from bivariate correlation analyses showed that extraversion was positively associated with both aggressive and considerate behavior, while neuroticism was positively correlated with aggressive behavior and negatively associated with considerate behavior. Multiple hierarchical regression analyses revealed that the effect of neuroticism on both aggressive and considerate behavior was partially mediated by whether drivers were positive or negative toward sharing the road with bicyclists (attitudes). Regression analysis also showed that extraversion moderated the effect of attitudes on considerate behavior. It is proposed that these findings may be explained in light of the five-factor personality framework, the frustration-aggression model and personal maladjustment theory. Possible implications of the findings are discussed.