Technologies for user notification suppression include a user notification controller that controls a presentation of notifications to a user. The user notification controller includes a user notification determiner that determines whether a user notification is to be presented to the user, a user activity analyzer that determines an activity of the user, and a notification suppressor. The notification suppressor determines whether the determined activity of the user is indicative of the user's knowledge of information included in the user notification prior to the presentation of the user notification to the user. In response to a determination that the determined activity of the user is indicative of the user's knowledge of the information included in the user notification, the notification suppressor suppresses the presentation of the user notification to the user.