With public commitments to solely source cotton from sustainable sources in the near future by the largest international brands and retailers, the production of sustainable cotton (e.g. Cotton made in Africa and Better Cotton) is becoming crucial in textile and apparel production. This report investigates the requirements for achieving a breakthrough of sustainable cotton production in Ethiopia, an East African country that arises as new sourcing destination for major global brands and retailers. The Technological Innovation System (TIS) approach and its functional dynamics, in complementation with insights from the value chain approach and Multi Level Perspective (MLP) are used to reveal these requirements. The TIS approach complemented with insights from other literatures is experienced as very useful in the identification of requirements in a structured manner. Various requirements for achieving a breakthrough of sustainable cotton production are formulated and different roles for Solidaridad are identified. Furthermore, recommendations for further research are given to enhance the applicability of the TIS framework in providing useful guidelines for managing transitions in developing country contexts.