Over the past 20 years education for sustainable development (ESD) has become part of the discourse in teacher education and the teaching community has a better grasp of ESD's action-oriented and participatory pedagogies. The International Network of Teacher Education Institutions (TEIs) associated with the UNESCO Chair on Reorienting Teacher Education to Address Sustainability at York University in Canada began meeting in 2000. It has expanded to more than 65 countries where teachers have woven sustainability into existing courses as well as created courses, certificate programs and graduate degrees in ESD. They have created professional development opportunities for colleagues as well as local, national and international networks to advance ESD. They have started academic journals. Education ministries can now write policy requiring ESD as part of initial teacher preparation because there is on-the-ground practice to support such policies as well as TEIs that can provide professional development.