What is twinning? Twinning is a formal, substantive collaboration between two organizations seeking to achieve a common goal. Twinning encourages civil society organizations to collaborate and to form partnerships with like-minded organizations in other countries or regions and provides a platform for the exchange of knowledge and strengthening of capacity. Twinning is not a new concept. Many cities around the world have engaged in twinning for decades. In more recent years, organizations working in the fields of international development and HIV have joined forces through twinning projects.