An image processing system includes: a first image processing device including: an input unit that receives an input of first authentication information for authenticating a user based on a first authentication method; an authentication unit that performs authentication on an own device by using the first authentication information; and a cooperating unit that uses a function of one or more second image processing devices. The authentication unit transmits, when the cooperating unit is to be operated, the first authentication information to the one or more second image processing devices, and transmits, when authentication to a second image processing device based on the first authentication information has failed, a transmission request of authentication method information indicating a second authentication method of the second image processing device to the second image processing device, the authentication to which based on the first authentication information has failed.