A vehicle alertness control system that executes alertness control to increase an alertness level of a driver of a vehicle includes an alertness level determination unit, an alertness controller, and a conversation controller. The alertness level determination unit is configured to determine an alertness level of the driver. The alertness controller is configured to select a level of a stimulus applied to the driver based on the determined alertness level. The conversation controller is configured to select a conversation category corresponding to the selected stimulus level from conversation categories categorizing a content of utterance in correspondence with each stimulus level and control conversation with the driver through a speaker and a microphone.
