Dental bio film-related diseases are prevalent worldwide and represent a significant contribute to dental caries and periodontal disorders, under scoring the urgent need for natural alternatives to synthetic antimicrobials. Zonaria variegata, a brown seaweed rich in bioactive compounds, shows promise due to its potential antimicrobial, antioxidant, and antiinflammatory properties. Methodology: A crude methanol extract of Zonaria variegate was prepared via Soxhlet extraction. The extract was evaluated for its antimicrobial activity against Streptococcus mutans and Shigella sonnei using the well diffusion method. Its ability to inhibit bio film formation was assessed in vitro on glass substrates using crystal violet staining and microscopic analysis. The antioxidant activity was determined through the DPPH radical scavenging assay, while the anti- inflammatory potential was examined using a BSA denaturation assay. Results: The extract demonstrated a dose-dependent antimicrobial effect, with increased zones of inhibition observed against both S. mutans and S. sonnei. It significantly reduced bio film formation in a concentration-dependent manner. Moreover, the DPPH assay revealed notable antioxidant activity, and the BSA denaturation assay confirmed a marked antiinflammatory effect, evidenced by enhanced protein stabilization. Conclusion: The integrated antimicrobial, anti-bio film, antioxidant, and anti-inflammatory activities of Zonaria variegata extract highlight its potential as a natural alternative to synthetic dental therapeutics. These promising results warrant further research to isolate the active compounds and validate the clinical efficacy of the extract in managing dental bio film-related diseases.