The primary objective of this research is to develop a better understanding of consumer’s post-purchase psychological state by examining the influence of sales promotion and emotional brand attachment on post-purchase cognitive dissonance, taking into account the mediating role of impulse buying behavior. The current study addresses several gaps in literature. Firstly, it is hard to find the direct impact of sales promotion and emotional brand attachment on post-purchase cognitive dissonance. Secondly, to the best of our knowledge, few studies have investigated the mediating role of impulse buying behavior in consumer research. A sample of 256 respondents was collected from Pakistani retail consumers. The statistical findings of this study show that sales promotion has a significant positive effect on the impulse buying behavior and post-purchase cognitive dissonance. Furthermore, results indicate that emotional brand attachment has a negative influence on impulse buying behavior but has a significant positive impact on post-purchase cognitive dissonance. Meanwhile, impulse buying behavior is a potential mediator between sales promotion, emotional brand attachment, and post-purchase cognitive dissonance relationships. The moderating role of Gender describes that the positive relationship between sales promotion and post-purchase cognitive dissonance will be stronger for women as compared to men at a higher level of sales promotion.