Social value orientation (SVO) is a personality trait that is closely associated with social comparison preference. However, little is known about how the different types of SVO (i.e., proself vs. prosocial) modulate the behaviour and neural underpinnings of its interaction with social context. In the present study, we examined electrophysiological correlates captured when individuals with different SVOs engaged in a gambling game with two other players (a socially disliking player, person A, vs. a socially liking player, person B). Three main findings are reported in our study. 1) Social comparison effects were manifested in feedback-related negativity (FRN) (the most negative FRN was expressed in the large difference condition, and the least negative FRN was expressed in the even condition), and this effect was modulated by both the win/loss context and SVO. That is, in a self-win context, FRN exhibited a social comparison effect for both prosocials and proselfs. In the self-loss condition, only prosocials displayed this effect. 2) Both groups displayed an enhanced FRN to person A's (the disliked player's) loss compared with the FRN to A's win in the self-win context, whereas only prosocials displayed a more negative FRN to A's win compared to A's loss in the self-loss context. 3) There was a social liking effect, but not a social comparison effect, on the P300, showing that for prosocials only, winning with a socially liking player elicited an increased P300 compared to winning with a disliking player. These findings suggest that the influences of SVO on social comparison are automatic and context dependent, which is reflected by a semi-automatic FRN in which prosocials are sensitive to others' wins or losses in both the self-win and self-loss contexts, whereas proselfs are not interested in others' outcomes in the self-loss context. Furthermore, interpersonal relationships affected the P300 for prosocials when they won but had no effect on the proselfs. This work sheds light on the neural basis of outcome evaluation in multiple social contexts and its individual differences in automatic social comparison situations.