There are provided a printing control apparatus and printing system which can accurately print index information on the tab portion of a tab sheet without any print offset. A position where index information (Section 1-Section 5) is to be printed on each tab portion of a tab sheet set (300) (constituted by, e.g., five sheets) is set first. Index information is then printed in advance on a test printing sheet (310) (opaque sheet), together with boundary lines (L1-L3) indicating a print area, on the basis of the setting value. When a print offset amount in the horizontal direction is to be measured, a boundary line (L2) of the test printing sheet (310) is superimposed on the right end (iii) of an index area of the tab sheet set (300), and the distance (print offset amount) between an extension line (ii) of the boundary line (L2) and the left end (i) of the index area is measured. The index information (Section 1-Section 5) can be properly printed on the tab sheet set (300) upon resetting of the setting values by using the measurement value.