To provide a printing apparatus which can improve the user's ease of use by avoiding the user's trouble because of an operation of setting a size and a material of papers, a paper feed tray and the like before printing, and to provide a program and a printing system.

In the printing apparatus which has a receiving means for receiving printing data from an external device, a plurality of medium supply devices, and a memory in which medium information indicating correspondences between the medium supply devices and kinds of media is stored for each medium supply device, printing is carried out to the medium on the basis of the printing data with reference to the medium information. The printing data includes information which designates the kind of the medium and the medium supply device. The medium information is what is stored in the memory on the basis of the information included in the printing data.