The booming skincare market today is driving fierce competition among brands in the industry. Startups and micro-entrepreneurs face challenges in differentiating themselves and establishing effective connections with their audience. Understanding consumer behavior in the booming skincare industry, especially for small businesses competing against major brands, becomes crucial. We conducted this quantitative study to investigate the role of Personality traits – Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism and the Marketing Mix, encompassing Product, Price, Promotion, and Place on the online impulsive buying behavior of Gen Z consumers when making purchases of skincare products in the lens of the S-O-R Theory. The Stimulus-Organism-Response (SOR) framework provides a way to determine how environmental factors (stimuli) affect the formation of customers’ internal evaluation (organism), and ultimately lead to behavior (response). This online impulsive buying behavior often emerges in e-commerce due to easy access to skincare products and simple purchasing. Marketers can better harness impulsive buying tendencies by optimizing their tactics by determining which marketing mix factors best promote impulse purchases. Responses from the 165 Gen Z students in a public university were examined using a 5-point Likert Scale, and the results of the five personality traits were summarized and interpreted using the R programming tool. According to the survey, Agreeableness emerged as the most predominant trait among the Big Five Personality Traits, with 161 Gen Z respondents (97.58%) indicating very high levels of this trait. The study found that Openness positively moderates the Price, Promotion through celebrity endorsement, and Place, significantly predicting online impulsive buying of skincare products. Conversely, Conscientiousness exhibits a significant negative interaction, indicating that higher levels of Conscientiousness diminish the positive effect of celebrity endorsement on impulsive buying behavior. Notably, Extraversion, Agreeableness, and Neuroticism do not moderate the relationship between the marketing mix and online impulsive buying of skincare products. The study has implications for marketers and micro-enterprises in the skincare industry. The findings could be used to tailor and personalize marketing strategies to target consumers' impulsive online buying behaviors effectively. While the present study has examined the moderating effects of the Big Five Personality in the relationship between marketing mix and online impulsive buying behavior on skin care products among Gen Z IITians, future researchers may explore a broader geographical scope for the study to enhance the validity of the results and enable cross-country comparisons.

• Online Impulsive Buying

• Marketing Mix

• Big Five Personality Traits

• S-O-R Theory