Abstract: Systems, methods, and devices for dynamically authenticating a user are disclosed. A speech-controlled device captures a spoken command, and sends audio data corresponding thereto to a server. The server determines the audio data includes a spoken command to receive content, and therefrom determines a source storing the content. The server also determines threshold user authentication confidence score data associated with the content source. Based at least in part on the threshold user authentication confidence score data, the server determines a user authentication technique, and a device configured to capture user authentication data. The server determines user authentication confidence score data using user authentication data received from the device, and determines weighted user authentication confidence score data therefrom.