The research seeks to explore the leadership development approach within a civil society organisation (CSO) in a developing country and the connection to the Inner Development Goals (IDGs). Constructive- developmental theory and transcendent leadership provide the lens through which to explore how developing inner capacities can shape constructing new meanings of the world around us with a heightened understanding and awareness of complexity and interconnectedness. Semi-structured interviews were conducted with members of a CSO in the Philippines to gain insight into their perspectives of their own leadership development while engaging in the CSO. The study has uncovered the significant role that the CSO's leadership development approach plays in the development of the mental complexities of its members and leaders. This equips them with the capabilities required to navigate adaptive challenges and co-create sustainable solutions. These skills and capabilities are closely aligned with the IDGs.