Emotional display is often used as a strategy in negotiation to manipulate one's counterpart's behavior. Previous research has examined the interpersonal effects of emotions in negotiation, but the evidence so far has largely focused on the perspective of the negotiator displaying the emotion with little attention paid to the impact of the emotional display on that negotiator's counterparts. In this study, we conducted two experiments to examine whether a negotiator's perceptions about the authenticity of his or her counterpart's displayed emotions of anger and happiness moderate the impact of those emotions on the negotiator. In Experiment One, we manipulated the perceived authenticity of the counterpart's anger as a between‐subjects factor (authentic versus inauthentic). Negotiators who perceived their counterpart's anger as inauthentic conceded less than did negotiators who perceived it as authentic. In Experiment Two, we corroborated this finding with a two‐variable (counterpart's emotion: anger versus happiness) times three‐variable (perceived authenticity of counterpart's displayed emotion: authentic versus ambiguous versus inauthentic) between‐subjects design. Negotiators conceded more to an angry counterpart than to a happy one when they perceived their counterpart's emotion as authentic, but we found the reverse pattern among negotiators who perceived their counterparts' emotions as inauthentic. Negotiators who perceived their counterparts' emotions as ambiguous in authenticity did not differ in concessions whether the counterpart displayed anger or happiness. We discuss the theoretical and practical implications of these findings.