A maintenance notification system estimates a state of a target vehicle that is subjected to maintenance on a basis of at least one of status information and drive history information of the target vehicle; estimates a tendency of maintenance by a user on a basis of the status information of the target vehicle; selects index information to be used for identifying a timing for maintenance of the target vehicle on a basis of at least one of the status information and the drive history information of the target vehicle, and identifies the timing for maintenance of the target vehicle and a content using the estimated state, the estimated tendency of maintenance by the user, and the selected index information; and provides a notification relating to the maintenance on a basis of the timing for the maintenance and the content.