Green belts have been a part of the planning landscape for much of the 20th century, yet they have come under attack in recent years. The objective of this article is to inform the future of the green belt concept internationally and in the UK. We first examine recent policy changes in the UK, showing how green belts are being conceived more broadly to include the concept of green infrastructure. We then focus on Canadian green belts, and in particular that of Toronto, which exemplifies some of the challenges with integrating green belts and green infrastructure.