Devices, systems, and methods are provided for demographic matching and content selection for unidentified audiences. A method may include receiving, by a first device of a first device type, a request to present first content to a user of a first audience using a second device; determining a time at which the first content is to be presented to the first audience using the second device; identifying a second audience to which the second content is to be presented using devices of the first device type during a time period that includes the time; determining a probability that the user belongs to an audience group that includes users of the second audience based on the second content, the time period, and a second device type of the second device; and causing selection of the first content or third content for presentation to the first audience.