This research hopes to provide insights on the influence of external factors that trigger Impulse Buying Behaviour (IBB) in the Fast-Moving Consumer Goods (FMCG) products. This research includes external factors like Visual Merchandising, Packaging and Store Atmosphere that have been taken into consideration and their impact on Urge to Buy Impulsively (UBI) and IBB has hence been studied. Further, data was collected from 489 respondents who paid visits to malls and other type of stores; analysis was conducted through Structural Equation Modelling (SEM). Study considered 11 hypotheses and out of them 4 did not found support and significance. Results from the study shows that all variables had positive and significant relationship with IBB. In regard to UBI and IBB relationship, study found strong support. Relation of UBI with situational in-store factors shows that UBI have strong and significant relationship with visual merchandising and packaging except store atmosphere. Gender is not found to have an impact upon UBI and IBB, while age is found to be negatively related with IBB and non-related with UBI. With growing organized retail in world markets, study holds significant value and insights for marketers, retailers and theorists to understand impulsive behaviour of customer inside store.