The main aims of this two-wave prospective study were to (1) present different theoretical mechanisms for relationships between bullying and personality characteristics, (2) determine forward and reverse long-term associations between victimization from bullying and personality traits included in the five-factor model and (3) establish whether these personality traits contribute to the variance in bullying, beyond work environment factors in the form of role conflict and role ambiguity. The prospective sample comprised 3066 Norwegian employees. The time lag between the two measurement points was two years. Neuroticism significantly predicted subsequent bullying in analyses of direct associations between personality traits and victimization. When adjusting for role conflict and role ambiguity, conscientiousness emerged as the only significant predictor of later victimization from bullying. In tests of reverse associations, victimization from bullying at baseline was significantly related to agreeableness, conscientiousness and openness at follow-up. Taken together, the study findings indicate that personality traits may function as both predictors and outcomes of workplace bullying.