An image processing apparatus including a reading unit configured to read an image of a document to generate image data based on the read image acquires a process definition file, which defines a content of reading processing to be executed by the reading unit and a content of transmission processing for transmitting image data generated by the reading unit, causes the reading unit to execute reading processing to generate image data according to a definition included in the acquired process definition file, and, when a plurality of process definition files is selected and the selected plurality of process definition files is instructed to be executed, causes the generated image data to be transmitted according to a definition included in each of the selected plurality of process definition files.