This document discusses the role of non-governmental organizations (NGOs) in international negotiations using the Transatlantic Trade and Investment Partnership (TTIP) negotiations as a case study. It finds that NGOs established transnational advocacy networks that were successful in slowing down the TTIP negotiations and influencing the positions of key actors on issues like the investor-state dispute settlement mechanism. NGOs also engaged in normative reframing of the issues and proposed alternatives. While only achieving partial success in increasing transparency, NGO activism demonstrated the important role such groups can play in modern diplomatic dynamics.