In response to the complexity and mounting adaptive challenges of teaching, learning and leadership today, this article presents an overview of a new "learning-oriented model of school leadership," which is composed of four pillar practices--teaming, mentoring, collegial inquiry, and providing leadership roles--that support internal capacity building or adult development. This model draws from more than 20?years of research with school leaders and educators around the globe. After first underscoring the need to find more effective ways to build human capacity to better equip educators of all kinds to manage the growing adaptive challenges they face in schools, we next orient readers to Kegan' constructive-developmental theory, since it undergirds this model and the practices composing it. Third, we introduce each of the four pillar practices and discuss how they support capacity building in adults who make sense of their learning experiences in developmentally different ways. Last, we discuss key implications for implementing the model in different contexts. In particular, we highlight that: (1) A developmental perspective can help us understand that adults will experience professional learning opportunities, leadership experiences, and engagement in the pillar practices in qualitatively "different" ways; (2) A developmental vocabulary helps us move from labelling adults (e.g. as "resisters") based on behaviours toward a deeper understanding of our differing developmental capacities and the need to differentiate professional learning opportunities to support adults' growth; and (3) Learning about "and" attending to supporting other people's and our own growth (i.e. internal capacity building) can help us to enhance student achievement and build schools and systems that are better equipped to meet the complex challenges of leading and teaching our modern world. (Contains 2 notes and 7 tables.)