Human judgment is basically comparative. This also holds for self-evaluations, which come about through social comparison. When comparing themselves to others, individuals often conclude that they are in various respects better. Little is known, however, about the interpersonal consequences of such self-superiority beliefs when they are verbally communicated to others. This dissertation aims to fill this gap. More specifically, it tests the hypothesis that people’s reaction to another person’s self-superiority claims depends on what they believe these claims say about them, rather than about the claimant. People may express their self-superiority beliefs in an explicitly comparative manner, by saying that they are “better than others”, or in an implicitly comparative manner, by saying that they are “good”. Although both claims derive from social comparison and basically convey the same message, observers (i.e., people observing these claims) respond unfavorably to the former type of claim but favorably to the latter. According to the hubris hypothesis, which is at the basis of this dissertation, observers do so because they infer from explicit (more than from implicit) self-superiority claims that the claimant holds a negative view of other people and therefore of them. This chain of inferences makes observers react unfavorably to the claim and the claimant. This dissertation extends previous research on the hubris hypothesis in several manners. First, it shows that observers’ disapproval of explicitly comparative claims is specific to self-superiority claims and does not reflect an aversion to any overtly conveyed self-other difference. Second, it experimentally demonstrates the importance of the view that observers believe the claimant has of them in determining their reactions to self-superiority claims. It does so by investigating observers’ responses to various explicit self-superiority claims that either rule out or particularly strongly suggest that the claimant views them unfavorably. Third, this dissertation demonstrates the role of observers’ inference about how the claimant views them via mediation analyses as well. These analyses consistently support the causal path that according to the hubris hypothesis leads from an explicit self-superiority claim to observers’ disapproval. Fourth and finally, this dissertation presents a novel test and an extension of the hubris hypothesis. The novel test involves the identification of an additional determinant of observers’ reactions to self-superiority claims. Not only the type of claim (explicit versus implicit) but also the content of the claim (competence versus warmth) affects these reactions. Observers dislike superiority claims about competence more than superiority claims about warmth, with the former dimension being more important to their self-view. The extension is at the level of observers’ reactions to self-superiority claims. Observers do not only ascribe less desirable traits to explicit (versus implicit) self-superiority claimants and claimants bragging about competence (versus about warmth), but they also wish to affiliate less with them and react more aggressively to them. The latter finding demonstrates that self-superiority claims may function as provocations. In sum, this dissertation shows that, rather than flattering the claimant, self-superiority claimants are ultimately viewed as derogating the observer.