There is provided a piston ring which can sufficiently provide the sealability of the outer circumferential surface thereof and in which increase in oil consumption due to reduction of surface pressure and increase in frictional loss due to effects of wear can be reduced. A piston ring 1 is provided with an annular body 2 that includes: an inner circumferential surface 2c and an outer circumferential surface 2d; side surfaces 2a, 2b substantially orthogonal to the inner circumferential surface 2c; and a pair of joint ends 4, 5 which are opposite to each other to form a joint section 3. The outer circumferential surface 2d includes an inclined surface 11 and an abutment surface 12 that is provided on the side surface 2b side of the inclined surface 11 and that extends substantially parallel to the inner circumferential surface 2c. The maximum width W1, of the abutment surface 12, at the joint ends 4, 5 is 80-150% of the maximum width W2, of the abutment surface 12, at a main portion 6. In the body 2, the two-axis difference (d2 - d1) between a diameter d1 passing through the central position of the joint section 3 in a first axis direction and a diameter d2 in a second axis direction orthogonal to the first axis direction is greater than -0.25 mm and less than +0.36 mm.