This study is the first to explore the accountability mechanisms and the degree of transparency of German NGOs for their projects performed in Haiti from 2010 until 2018. While examining to whom, for what, and how German NGOs were accountable during this period, the research investigated German NGOs' level of aid effectiveness and developmental impacts since Germany was among those parties which ratified the Paris Agreement on aid effectiveness, and German NGOs received significant donations from the German official aid development to implement projects worldwide, especially in Haiti. During the past decade, accountability demands from NGOs have significantly increased due to frequent financial and ethical scandals occurring in the nonprofit sector. Taking an adapted stakeholder theory approach, this study developed an understandable view of the accountability relationship for improving Ngo's aid effectiveness and developmental impacts in Haiti. In exploring the accountability procedures of three German NGOs, the study examined the important role public policy can play in strengthening the accountability and transparency practices of German NGOs.