Our team

Sotiris Petropoulos


During my PhD studies, I came across the Civil Society and non-profit organizations. Since 2009, I am focusing on the NGO ecosystem, in particular through the research program “Thales-Evaluation of Greek NGOs”. In 2012, I started organizing a series of capacity-building seminars directed to organizations throughout Greece. Having met people from more than 200 NGOs, I can maintain my positive attitude and smile since all the elements for fascinating initiatives are out there. My aspiration is to support as much as possible the Greek ecosystem.
Sotiris holds a Bachelor’s degree in Shipping, a MA in International Political Economy and a PhD focusing on Regionalism in the Developing World.

Aris Souras


After six years in a multinational company, I resigned in 2014 to co-create a startup in the area of music, while participating in the Athens Center For Entrepreneurship And Innovation |the incubator center of the Athens University of Economics and Business| as a Marketing & Communications Mentor. During the last years, I have been a key lecturer in the capacity-building seminars entitled “Planning, Implementation and Evaluation of Developmental Programs” offered to NGOs executives throughout Greece, organized by the University of the Peloponnese, with the support of the Stavros Niarchos Foundation. Working at HIGGS will enable me to offer program participants my knowledge coupled with my experience from the multinational field, the startup ecosystem and the NGO environment.
Aris studied Political Science and Public Administration and holds a MA in Marketing & Management from the University of Bradford.

Katerina Matiatou


I found myself in the ΝGO ecosystem by mere luck in 2008. Since then, luck has transformed to enthusiasm and love! Having acquired experience at the “Royal Academy of Arts”, “Special Olympics” and “Future Library”, my path led me to “Desmos”, where I became familiar with the vision and work of hundreds of NGOs across Greece, via the majority of Desmos’ nationwide programs. As part of HIGGS, I want to share everything I’ve learned with other organizations and help them to be effective and sustainable.
Katerina has studied Communication, Media and Culture and holds an MA degree in Cultural & Creative Industries.

Archonto Antonatou

Assistant Manager

Newsletter / Website / Research & Administrative Support

My work experience in 5 NGOs involved in different fields (refugees, education, vulnerable and socially excluded groups) and my participation at the Vodafone «World of Difference program» in 2015, helped me further understand the challenges that the organizations face in their attempts to achieve their objectives. Through my work at HIGGS, I hope to make a valuable contribution to the Greek NGO ecosystem by meeting their needs. I am glad to be part of a team with a common vision and the desire to “help those who help”!
Archonto has studied International Relations and holds a MSc degree in International Development.

Katerina Velliou

Assistant Manager

Events / Communications / Research & Administrative Support

Since 2012 I have worked in 3 NGOs with different scopes: environment, social vulnerability and education. My work consisted in supporting them in the areas of Administration, Marketing and Fundraising. In particular, my three-year experience in a newly established organization and my current contact with the organizations of HIGGS programs have showed me how much enthusiasm and sincere willingness there is in the Greek NGO eco-system, and how much need there is for training, networking and better coordination. As a member of the HIGGS group, I hope to stand by them, supporting their vision and strengthening their efforts.
Katerina has studied Law at the Democritus University of Thrace.

Katerina Kaisari

Assistant Manager

Fundraising/ Reasearch & Administrative Support

During my studies, I acquainted with the Third Sector that spurred my interest in working on this sector both at academic and professional level. In particular, I had the opportunity to come into contact with the Greek ecosystem of NGOs in terms of my master thesis, studying the relationship between the Greek state and NGOs in the face of the refugee crisis in Greece. As a part of the HIGGS team, I hope to significantly contribute to the development and sustainability of the ecosystem of NGOs in Greece.
Katerina has studied Political Science and Public Administration with Master of Science in Crisis and Security Management. PhD candidate in the Faculty of Political Science and International Relations at the University of Peloponnese.