This study examined the influence of social media marketing on consumer purchasing behavior in Jumia Uganda. Social media platforms have become indispensable tools for e-commerce operators seeking to engage, inform, and convert prospective customers. The study specifically investigated how content marketing, influencer endorsements, targeted advertising, and interactive engagement on platforms such as Facebook, Instagram, TikTok, and Twitter affect the purchasing decisions of Jumia Uganda's customers. A descriptive and correlational research design was adopted, and data were collected from 248 respondents who were active Jumia Uganda users. Structured questionnaires were the primary data collection instruments, supplemented by interviews with selected digital marketing personnel. The findings revealed a statistically significant positive relationship between social media marketing activities and consumer purchasing behavior (r = 0.673, p < 0.01). Regression analysis further demonstrated that social media marketing explains 45.3% of the variance in consumer purchasing behavior (R² = 0.453). The study concluded that social media marketing is a pivotal determinant of purchasing decisions among Ugandan online shoppers and recommended that Jumia Uganda intensify its investment in localized, culturally relevant, and datadriven social media campaigns.