This paper examines the conditions that foster downward accountability among nongovernmental organizations (NGOs). To do so, I compare how NGOs responded in an unusual case where, from 1999-2003, the Zapatista Movement demanded more say over projects. I compare 77 NGOs, some that dropped out and others that accommodated the movement's demands. I argue that funders' reporting requirements inhibited NGOs from being responsive to beneficiaries. However, living alongside the movement pushed inner-circle NGOs to practice downward accountability to sustain their legitimacy. In turn, horizontal pressure among NGOs influenced organizations further afield, especially those that identified closely with the movement.