In a printing system capable of supplying a sheet of a job having undergone print processing by the printing unit of a printing apparatus to a post-processing unit capable of executing at least a specific type of post-processing among a plurality of types of post-processes, when the target job requires the specific type of post-processing, the printing apparatus is inhibited from executing print processing of the job without explicitly determining a sheet necessary for the print processing of the job by a user using a user interface unit. When the target job does not require the specific type of post-processing, the printing apparatus is permitted to execute print processing of the job without explicitly determining a sheet necessary for the print processing of the job by the user using the user interface unit.