This study examined the role of social media in promoting postmodernist culture among undergraduate students of Nasarawa State University, Keffi. Specifically, it investigated students' exposure to postmodernist content, the dominant themes conveyed through social media, the influence of digital platforms on postmodernist ideas, and the platforms most frequently used by undergraduates. A mixed-method research design was adopted. Data were collected through questionnaires administered to 200 students, with 193 valid responses retrieved, representing a 96.5% response rate. Focus Group Discussions (FGDs) complemented the survey data. Quantitative data were analysed using frequencies and percentages, while qualitative data were analysed thematically. The findings revealed high exposure to social media, with TikTok, Instagram, Facebook, WhatsApp and X serving as the major platforms. Entertainment, fashion, memes, lifestyle content and identity expression emerged as dominant themes. The study concludes that social media promotes postmodernist culture among undergraduates and recommends digital media literacy and responsible social media use.