Methods and apparatus for invoking a security feature of a computing device display in response to detecting an onlooker based on depth data are disclosed. An example apparatus includes at least one memory, computer-readable instructions, and processor circuitry, The processor circuitry is to execute the computer-readable instructions to automatically invoke an onlooker detection model of a computing device in response to determining that the computing device is located in a public, unsecure environment. The onlooker detection model is to detect an onlooker based on data collected by a sensor associated with the computing device. The processor circuitry is to execute the computer-readable instructions to automatically invoke a security feature of a display of the computing device in response to detection of the onlooker.