The structure of India's capital market has undergone a structural transformation over the last decade, marked by a substantial increase in retail investor participation alongside sustained dominance of institutional investors. This study examines the comparative participation, investment behavior, ownership patterns, and market impact of retail and institutional investors in India. Using secondary data from regulatory bodies such as the Securities and Exchange Board of India (SEBI), National Stock Exchange (NSE), and the Association of Mutual Funds in India (AMFI), the study analyses trends between 2014 and 2025. The findings indicate that retail investors have emerged as a significant force in liquidity generation and market sentiment, while domestic institutional investors have increasingly stabilized markets during periods of foreign capital outflows. The paper concludes that the coexistence of retail expansion and institutional consolidation has enhanced market depth but necessitates stronger financial literacy and regulatory safeguards.