The spectacular topography of the Tibetan Plateau is the result of collision between India and Eurasia over some 50 Myr, but how the plateau grew to its present size remains a topic of debate. Work along its eastern margin suggests a two-stage uplift (thus growth of the plateau) since 30-25 Myr. Here we report high-resolution seismic reflection and drill core results from the southern Tarim Basin that indicate a similar pattern for the northern margin of the plateau. The data suggest that uplift in northern Tibet started at ~23 Myr from near sea level, with the first episode finished by ~10 Myr, followed by a post-5-Myr episode of rapid uplift along the present plateau margin. The growth of the Tibetan Plateau after the Eocene thus appears to have been episodic in nature, and near-synchronous along both eastern and northern margins.