Taking sides is one of the reactions available to third parties in handling a dispute. From the perspective of individual differences, this study was aimed at identifying lay third parties’ motives for side taking and exploring their relations with the Big Five personality traits. We tested our assumptions using three samples: A Dutch student sample ( n = 111), a Dutch employee sample ( n = 101) and a Chinese student sample ( n = 124). The findings revealed four types of side–taking motives: Moral, relational, reward–approaching and sanction–avoiding motives. The results also showed that individuals’ personality traits were relevant to the four types of side–taking motives: Agreeableness was associated with the relational motive for side taking, and intellectual autonomy was associated with the reward–approaching motive, the sanction–avoiding motive and the relational motive for side taking. Implications and explanations of these findings are discussed. Copyright © 2010 John Wiley & Sons, Ltd.