The rapid growth of digital technology has transformed the way businesses promote their products and services, with online advertising emerging as a key tool for sales promotion. This study examines the impact of sales promotion through online advertising on consumer buying behaviour. It focuses on how various digital platforms such as social media, websites, and mobile applications influence consumers’ awareness, interest, and purchase decisions The research analyses different types of online sales promotion techniques, including discounts, coupons, limited-time offers, and influencer marketing, and evaluates their effectiveness in attracting and retaining customers. Data collected from respondents highlights the role of convenience, accessibility, and personalized advertising in shaping consumer preferences.