A printing apparatus includes: a sheet discharge tray having an upstream portion tilted to extend downward in a direction of gravity; an upper member limiting a height of a space above the sheet discharge tray; a full sensor configured to detect an upstream end of a top sheet of sheets stacked on the sheet discharge tray; a counter configured to count a number of the sheets discharged onto the sheet discharge tray; and a controller. The controller determines whether to stop discharging of the sheets to the sheet discharge tray, based on a detection result of the full sensor upon the sheets to be stacked on the sheet discharge tray including only sheets each with uniform thickness and based on a count value of the counter upon the sheets to be stacked on the sheet discharge tray including a sheet with thickness varying partly.