Benefit from a full range of professional expertise
About Us
Principal Consultant, Coach and Team Coach
Tosca is an experienced nonprofit, NGO and philanthropy-focused consultant, leadership development trainer and coach, team coach, change management expert, facilitator, author, and speaker with strong knowledge of nonprofit and NGO organizational effectiveness, team effectiveness, leadership development, organizational change management, governance, international development, and gender and leadership. Co-author of the acclaimed book ‘Between Power and Irrelevance: The Future of Transnational NGOs’, with Hans Peter Schmitz, George Mitchell, and Barney Tallack (Oxford University Press, 2020; second edition late 2026). Co-author of several academic articles in peer reviewed journals; author of many practitioner-oriented reports, blog posts and essays. Podcast host of ‘NGO Soul + Strategy’ (2020-2025).
Prior to founding Five Oaks Consulting, Tosca worked in a European think tank focused on governance in Sub-Sahara Africa and the Caribbean. She served various UN agencies and an American NGO in Cambodia, and worked as Social Development Specialist at the World Bank in both Washington DC and Vietnam. Tosca was also a ‘pracademic’ at the Maxwell School of Citizenship and Public Management at Syracuse University, USA, where she directed the Transnational NGO (TNGO) Initiative. The TNGO Initiative focused on the governance, leadership development and effectiveness of transnational NGOs.
Tosca is a dual Dutch and American national who has worked in multiple regions around the globe and who currently is living in the United States. The name of her consulting practice, Five Oaks Consulting, is the English translation of her difficult-to-pronounce Dutch last name.
Consulting philosophy
Tosca believes in accompaniment, not ‘sage on the stage’ or ‘fly in, fly out’ styles of consulting. She prefers to work with a defined set of organizations over a longer period, as a result of which mutual trust, honesty and truly deep understanding of the organizational identity, mindset and DNA (culture) of client organizations is growing ever stronger. Tosca typically works with mid to large size nonprofits and NGOs, although she also enjoys working with small, start-up, ‘rebel’ type of nonprofit actors who challenge the sector’s ways of working.
Our Commitment
For our longer term consulting/coaching/team coaching engagements: if at any point in our first 30 days of working together you decide that we are not meeting the standards described in our contract, just request a refund and we will send your money back, no questions asked.
The Five Oaks Consulting Support Team
It takes a village to raise a child. And in just the same manner, it takes the talent of multiple people to build a consulting practice. Without the support services of Ahmed, Piyali, Han, Heather and Jenell, we would have never gotten to where we are now!
Collaborators
Ramesh Singh
Consultant
Ramesh Singh is an INGO practitioner turned freelance consultant and advisor. Ramesh has depth of passion, experience, sense and curiosity about INGO architecture, governance, strategy and accountability systems and issues. He has worked in/from Africa, Asia, Europe and North America.
Barney Tallack
Consultant
Barney is a strategy person who acutely understands INGOs’ organizational dynamics, including their politics and DNA. His collaborative skills make him a pleasure to work with. Barney focuses on INGO strategy development, horizon scanning, governance and organizational change processes.
Minoli de Bresser
Consultant
Minoli is a poverty reduction and social inclusion specialist who has worked for some 30 years in the Asia Pacific and African regions, largely for the United Nations. She has a passion for designing and evaluating development programs through poverty reduction, social inclusion and gender equality lenses.
Bruce Dayton
Consultant
Bruce is dedicated to helping INGOs to better understand conflicts and crises, and to develop strategies to deal with them more constructively. He serves as Executive Director of the School for International Training’s CONTACT Peacebuilding Program in the US, and heads its Master’s degree program for mid-career NGO practitioners in Peace and Justice Leadership.
Ahmed Hachelaf
Consultant
Ahmed is an educator and NGO professional with over 13 years of experience in development, research, and training. He has managed cross-border projects, designed capacity-building programs in human rights education, and co-founded the Twiza and Mouakhat Projects.
Ahmed holds a Master’s in Public Administration from Syracuse University’s Maxwell School and a Doctorate of Science from the University of Algiers II. Currently, he serves as a Peace & Conflict Education Specialist at Generations for Peace Institute.