This study seeks to find out online impulse buying behaviour in the Pakistan e-commerce industry by investigating the contributing factors of money availability, time availability, family influence, serendipitous information and scarcity messages towards online impulse buying behaviour. It investigated the mediating role of the urge to buy impulsively between the factors and online impulse buying behaviour. From a sample of 472 students of 4 Pakistani universities, the data was gathered. Moreover, to analyze the data and to test hypotheses, PLS-SEM was employed, which showed money availability, time availability, scarcity messages, serendipitous information, family influence were significantly related to online impulse buying behaviour. The findings will be helpful for e-retailers in creating e-marketing strategies, delivering their promises and generating sales through effectively designing their promotional plans.