Abstract: A shingle gage is provided for aligning a second row of shingles to a first, lower row of shingles fixed to a roof or like structure so that the shingle rows are parallel to and spaced from each other. The shingle gage includes a first member having a first alignment surface which abuts against one longitudinal edge of the fixed row of shingles. A second member is attached to the first member of the shingle gage and includes a second alignment surface adapted to abut against one longitudinal edge of the second row of shingles. The first and second alignment surfaces are parallel to each other so that, with an abutting engagement obtained between the respective alignment surfaces and the first and second row of shingles, the second shingle row is aligned parallel to the first row of shingles and then secured to the roof. In addition, the second member is adjustably attached to the first member so that the spacing between the alignment surfaces is adjustable.