In the presence of business groups, the expropriation through related party transactions (RPTs) is common and costly to minority shareholders. Using the setting of India's RPT voting rule, I find that a majority‐of‐minority shareholder voting mechanism helps mitigate expropriation. Minority shareholders actively raise their voice against RPT resolutions. A difference‐in‐differences analysis reveals that shareholder voting has a significant deterrence effect on RPT volume. I also find that stock markets react positively to the voting rule's passage, and that the rule makes Indian firms more attractive to foreign institutional investors.