In one example, a sheet media alignment system includes: a guide (12) defining a curved media path (14) that extends from an upstream part of the guide to a downstream part of the guide; a movable blocker (16, 56) to block the curved media path (14) at the downstream part of the guide, the blocker movable into and out of a blocking position in which the blocker is spaced from the downstream part of the guide a first distance; and a driver (24, 58) upstream from the curved media path to drive a media sheet into the guide along the curved media path and into the blocker. The driver is spaced from the upstream part of the guide a second distance greater than the first distance such that a media sheet driven into the blocker will buckle between the driver and the guide before it will buckle between the guide and the blocker.