Aircraft window frame attachment system, comprising - at least one stringer having two parts separated by a cutout, - a window frame (1; 100) having an aperture (3; 103) there-through, an inner (5, 105) and an outer (7, 107) portion surrounding the aperture (3; 103), and window frame through-holes (5a, 5b, 7a, 7b; 105a, 105b, 107a, 107b) arranged on a circumference of the window frame (1; 100), wherein a tangential portion or an extension of the outer portion (7, 107) together with first window frame through-holes (7a; 107a) defines a first window frame portion (15; 115), and wherein a remainder of the window frame (1; 100) together with second window frame through-holes (5a, 5b, 7b; 105a, 105b, 107b) defines a second window frame portion (17; 117), and - a stringer coupling having a first stringer coupling portion, a second stringer coupling portion extending on each opposite side of the first stringer coupling portion and being attached to a respective one of the two stringer parts, and first stringer coupling through-holes arranged in the first stringer coupling portion, and second stringer coupling through-holes (119b, 119c) arranged in the second stringer coupling portion, wherein the first stringer coupling portion is attached to the first window frame portion (15; 115) in an overlapping arrangement such that the first window frame through-holes (7a; 107a) coaxially overlap with the first stringer coupling through-holes, and wherein the first window frame through-holes (7a; 107a) and the first stringer coupling through-holes have different diameters. - at least one stringer having two parts separated by a cutout, - a window frame (1; 100) having an aperture (3; 103) there-through, an inner (5, 105) and an outer (7, 107) portion surrounding the aperture (3; 103), and window frame through-holes (5a, 5b, 7a, 7b; 105a, 105b, 107a, 107b) arranged on a circumference of the window frame (1; 100), wherein a tangential portion or an extension of the outer portion (7, 107) together with first window frame through-holes (7a; 107a) defines a first window frame portion (15; 115), and wherein a remainder of the window frame (1; 100) together with second window frame through-holes (5a, 5b, 7b; 105a, 105b, 107b) defines a second window frame portion (17; 117), and an aperture (3; 103) there-through, an inner (5, 105) and an outer (7, 107) portion surrounding the aperture (3; 103), and window frame through-holes (5a, 5b, 7a, 7b; 105a, 105b, 107a, 107b) arranged on a circumference of the window frame (1; 100), wherein a tangential portion or an extension of the outer portion (7, 107) together with first window frame through-holes (7a; 107a) defines a first window frame portion (15; 115), and wherein a remainder of the window frame (1; 100) together with second window frame through-holes (5a, 5b, 7b; 105a, 105b, 107b) defines a second window frame portion (17; 117), and - a stringer coupling having a first stringer coupling portion, a second stringer coupling portion extending on each opposite side of the first stringer coupling portion and being attached to a respective one of the two stringer parts, and first stringer coupling through-holes arranged in the first stringer coupling portion, and second stringer coupling through-holes (119b, 119c) arranged in the second stringer coupling portion, wherein the first stringer coupling portion is attached to the first window frame portion (15; 115) in an overlapping arrangement such that the first window frame through-holes (7a; 107a) coaxially overlap with the first stringer coupling through-holes, and wherein the first window frame through-holes (7a; 107a) and the first stringer coupling through-holes have different diameters. a first stringer coupling portion, a second stringer coupling portion extending on each opposite side of the first stringer coupling portion and being attached to a respective one of the two stringer parts, and first stringer coupling through-holes arranged in the first stringer coupling portion, and second stringer coupling through-holes (119b, 119c) arranged in the second stringer coupling portion, wherein the first stringer coupling portion is attached to the first window frame portion (15; 115) in an overlapping arrangement such that the first window frame through-holes (7a; 107a) coaxially overlap with the first stringer coupling through-holes, and wherein the first window frame through-holes (7a; 107a) and the first stringer coupling through-holes have different diameters.