Purpose: This study examines the impact of social media marketing on consumer buying behavior among online consumers, and investigates the roles of consumer engagement, influencer marketing, and brand trust including whether brand trust mediates the relationship between social media marketing and buying behavior.

Variables: The study models social media marketing, consumer engagement, influencer marketing, and brand trust as antecedents of consumer buying behavior, with brand trust additionally examined as a mediator.

Methodology: A quantitative, cross-sectional design was adopted. Data were collected from 200 active social media users from Jodhpur through a structured questionnaire measured on a five-point Likert scale, using convenience sampling, and analyzed in SPSS and Excel via reliability analysis, descriptive statistics, Pearson correlation, and multiple regression to test five hypotheses.

Major findings: All scales were reliable (Cronbach’s alpha > 0.80). Social media marketing (β = 0.32), brand trust (β = 0.28), consumer engagement (β = 0.24), and influencer marketing (β = 0.22) each significantly and positively predicted buying behavior (all p < .01), supporting H1–H4. Brand trust was found to mediate the relationship between social media marketing and buying behaviour, supporting H5.

Practical implications: Marketers should pair interactive, engagement-driven social media campaigns and credible influencers with transparent communication that builds brand trust, since trust both directly strengthens buying behavior and channels the effect of social media marketing.