An image processing apparatus includes an internal obtaining device configured to obtain authentication information, a communication unit configured to perform communication with an external obtaining device that is configured to obtain authentication information, an image processing unit configured to execute at least one of image reading and image formation, and a controller configured to execute determination processing including granting a permission for executing image processing by the image processing unit when the controller determines that the authentication based on the authentication information obtained from the internal obtaining device and first reference information is successful, and granting the permission for executing the image processing when the controller determines that the authentication based on the authentication information obtained from the external obtaining device and second reference information is successful, the second reference information being different from the first reference information.