The rapid growth of the internet has altered shopping behaviors, increasing online impulse buying behavior. However, Shopee experienced a decrease in the number of website visits, signifying a decline in consumer engagement. Therefore, the writer researches to study the Big Five Personality Traits as factors that might influence online impulse buying behavior. The Big Five Personality Traits, comprising openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism are closely linked to customer interactions with online platforms, spontaneous buying decisions, and impulsive purchase, depending on personal characteristics and emotional states. The study employed the IBM SPSS V.30 for quantitative research. Both descriptive and causal approach were used. The research was conducted on a sample of 100 individuals utilizing convenience sampling. This study passed the validity, reliability, normality, multicollinearity, heteroscedasticity and multiple linear regression test, resulting in the regression equation � = 2.562 + 0.090�1 + 0.135�2 + 0.165�3 + 0.101�4 + 0.134�5. Based on the hypothesis testing results, the Big Five Personality traits influence online impulse buying behavior of Shopee Medan customers, either partially or simultaneously. Additionally, the Big Five Personality traits influence 72.4% of online impulse buying behavior. The writer suggests Shopee to include elements that encourage creativity and idea cultivation, provide clearer guidance and decision-making tools, improve feedback features, incorporate more prominent and accessible social responsibility features, and improve customer assistance. / Perkembangan internet yang pesat telah mengubah pola belanja dan meningkatkan perilaku pembelian impulsif online. Namun, Shopee mengalami penurunan jumlah kunjungan situs web, yang menandakan penurunan keterlibatan konsumen. Oleh karena itu, penulis meneliti untuk mempelajari Big Five Personality Traits sebagai faktor yang mungkin mempengaruhi perilaku pembelian impulsif online. Big Five Personality Traits, yang terdiri dari openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism erat dengan interaksi pelanggan dengan platform online, keputusan pembelian spontan, dan pembelian impulsif, tergantung pada karakteristik pribadi dan keadaan emosional mereka. Penelitian ini menggunakan IBM SPSS V.30 untuk penelitian kuantitatif Pendekatan deskriptif dan kausal digunakan. Penelitian dilakukan pada sampel 100 individu dengan menggunakan teknik convenience sampling. Penelitian ini lulus uji validitas, reliabilitas, normalitas, multikolinearitas, heteroskedastisitas, dan uji regresi linier berganda, menghasilkan persamaan regresi � = 2.562 + 0.090� 1 + 0.135� 2 + 0.165� 3 + 0.101� 4 + 0.134� 5. Berdasarkan hasil uji hipotesis, Big Five Personality Traits mempengaruhi perilaku pembelian impulsif online pelanggan Shopee Medan, baik secara parsial maupun simultan. Selain itu, Big Five Personality Traits berpengaruh 72,4% terhadap perilaku pembelian impulsif online. Penulis menyarankan Shopee untuk memasukkan elemen yang mendorong kreativitas dan pengembangan ide, menyediakan panduan yang lebih jelas dan alat pengambilan keputusan, meningkatkan fitur umpan balik, menggabungkan dan meningkatkan fitur tanggung jawab sosial, serta meningkatkan bantuan pelanggan.