We examine the governance implications of passive fund growth. In our model, investors allocate capital between passive funds, active funds, and private savings, and funds' fees and ownership stakes determine their incentives to engage in governance. If passive funds grow because of easier access to index investing, governance improves, albeit only up to a point where passive funds start primarily crowding out investors' allocations to active funds rather than private savings. In contrast, if passive funds grow because of reduced opportunities for profitable active management, governance worsens. Our results reconcile conflicting evidence about the effects of passive ownership on governance.