The Qinghai–Tibet, Iran, and Mongolia plateaus constitute the largest continuous mountain belt on Earth and harbor the world’s richest temperate alpine ecosystem, but the original timing and evolutionary causes of their biodiversity are poorly understood. Here, we review the geologic and phylogenetic evidence and compare it with the formation processes of the three plateaus. We show that the formation of the three plateaus is a major driver for change in the Asian landscape and biotas. Among the three plateaus, the Qinghai–Tibet Plateau has the most ancient evolutionary history and hosts the oldest biotic components and the highest biodiversity. The Neogene was a period of marked diversification across the three plateaus, thus leading to the formation of modern biotas.