Abstract: There is provided systems and methods for two-factor authentication through ultrasonic audio transmissions. A user may utilize a first device request to process a transaction electronically by providing an electronic payment using an online service provider. When utilizing the service provider, authentication for the user's payment instrument and/or the user's account with service provider may require two-factor authentication using a one-time password that is unknown to the user and generated for the specific authentication request. The password may be generated and sent to a second device registered for the user and/or their account. The second device may process an ultrasonic handshake request with the first device, and may respond to the first device with an ultrasonic communication including the password. The first device may then automatically enter the password to the two-factor authentication process.