The magnitude and extent of global change during the Cenozoic are remarkable, yet the impacts of these changes on biodiversity and the evolutionary dynamics of species diversification remain poorly understood. To investigate this question we combine palaeontological and neontological data for the angiosperm order Fagales, an ecologically important clade of c. 1370 species of trees with an exceptional fossil record. We show differences in patterns of accumulation of generic diversity, species richness, and turnover rates for Fagales. Generic diversity evolved rapidly from the Late Cretaceous and peaked in the Eocene or Oligocene. Turnover rates were high during periods of extreme global climate change, but relatively low when the climate remained stable. Species richness accumulated gradually throughout the Cenozoic, possibly at an accelerated pace after the Middle Miocene. Species diversification was into new environments: Quercoids radiating in Oligocene subtropical seasonally arid habitats, Casuarinaceae in Australian pyrophytic biomes, and Betula into late Neogene holarctic habitats. These radiations were counterbalanced by regional extinctions in late-Neogene mesic warm-temperate forests. Thus overall diversification at species level is linked to regional radiations of clades with appropriate ecologies exploiting newly available habitats.This article is protected by copyright. All rights reserved.