Instagram user-generated content (UGC) has become an important source of product information and consumer engagement, potentially shaping purchasing decisions. This study examined the relationship between Instagram UGC and consumer buying behaviour among young consumers in Guntur District, Andhra Pradesh, India. A quantitative, descriptive research design was employed, and primary data were collected through a structured Google Forms questionnaire using convenience sampling. The final sample comprised 78 Instagram users (n=78). The data were analysed using frequencies, percentages, means, standard deviations, Cronbach’s alpha (α), Spearman’s rank-order correlation (ρ), and simple linear regression (R2). The descriptive findings indicated that 69.7% of respondents had purchased directly through Instagram posts, reels, or shopping tags either frequently or occasionally, while 94.9% searched for user reviews at least sometimes. Influencer recommendations and reviews or testimonials emerged as prominent types of influential UGC. Hypothesis testing identified significant positive associations between UGC perceptions and reported purchasing behaviour (ρ=.77, p<.001) as well as purchase intention (ρ=.72, p<.001). Confidence associated with review and unboxing videos was also positively associated with reported purchasing behaviour (ρ=.65, p<.001). However, review-seeking behaviour and perceived credibility relative to brand advertisements were not significantly associated with their respective outcomes (p≥.05). The findings highlighted the relevance of UGC perceptions and review-based video content in understanding consumer responses to Instagram marketing. The use of convenience sampling, self-reported data, and a cross-sectional design limited generalisability and causal interpretation.