Near universal participation in higher education has been a huge achievement for OECD countries. Yet, globalization and geopolitical shifts, an ageing population, the technological and digital revolutions leading to increasing use of automation and AI, and strategies for sustainable green and blue economy will continue to reshape our societies, how and where we live and the world of work. What are the implications for our model of educational provision which has remained relatively unchanged as if it was still a system catering to a small elite? Attention is drawn to the other 50% – learners gradually being “left behind” by the current system and/or unable to access the system in any meaningful or sustained way. Much more radical thinking is required as to how we structure, govern, fund, and deliver post-secondary/post-compulsory education. This is driving many countries to reframe the policy discussion around the tertiary education eco-system, inclusive of formal, non-formal, “second-chance” and life-long learning opportunities. But, beyond the headlines what do we mean by tertiary education? What do we want to achieve? This paper begins by reflecting on the concept of systems and raises the idea of a tertiary ecosystem. It then looks at some factors driving the shift to tertiary education and reflects on some international responses.