AbstractThis research examines the impact of buyer–seller similarities (dissimilarities) in Big Five personalities—agreeableness, conscientiousness, extraversion, openness, and neuroticism—on impulsive buying in a dyadic setting. The study further analyzed how the interaction intensity and sensory stimulation mediate the effect of buyer–seller similarities (dissimilarities) on impulsive buying. The authors gathered 1020 dyad data from various beauty salons located in China to achieve research objectives. Difference score analysis was used to compute buyer–seller similarity (dissimilarity), and a variance‐based structural equation modeling technique was applied to analyze the data. The results indicate that the similarity of dyads in agreeableness and openness increases impulsive buying, while similarity in neurotic dyads decreases impulsive buying. Furthermore, interaction intensity mediates the relationships of dyads' similarities—in extraversion and openness—with impulsive buying, while buyers' sensory stimulation mediates the associations of buyer–seller dyads' similarities—in extraversion, neuroticism, and openness—with impulsive buying. Finally, this study provides several implications for marketers in the services industry.