A disc brake caliper comprising a caliper body arranged straddling a brake disc having a rotation axis defining an axial direction (A-A) and opposite friction surfaces, said caliper comprising pads accommodated in said caliper body so as to be able to slide substantially in an axial direction (A-A) with respect to the brake disc to act respectively on said opposite friction surfaces, said caliper comprising: - a cylinder, forming a cylindrical wall and a bottom wall transverse to the cylindrical wall; - a piston, forming a side wall and a thrust wall substantially transverse to the side wall and opposite to the bottom wall of the cylinder, wherein said bottom wall forms an inner surface facing towards the piston and an opposite outer surface facing opposite to the piston, wherein the piston is accommodated within the cylinder, and the side wall of the piston is adapted to slide within the cylindrical wall of the cylinder, wherein the piston is configured to be biased by a pressurized brake fluid injectable within the cylinder, to affect at least one of said pads against one of said brake disc friction surfaces, along a thrust direction substantially parallel to the axial direction (A-A), said caliper further comprising a parking-braking system which comprises a rotating member; said rotating member being rotatably accommodated within a rotation housing formed in the bottom wall of the cylinder so that the rotating member is rotatable about a rotation axis substantially parallel to the axial direction (A-A), wherein the cylinder defines a first annular housing and a second annular housing made in the bottom wall, said first and second annular housings (13, 14) extending into the bottom wall in a direction transverse to the axial direction (A-A) and leading into the rotation housing, said second annular housing being distinct from said first annular housing, and being positioned in a direction opposite to the inner surface of the bottom wall with respect to said first annular housing, wherein the first annular housing accommodates a first seal, and the second annular housing accommodates a second seal, and wherein the first and second seals (15, 16) are configured to act between said rotating member and said bottom wall of the cylinder to be fluid-tight; characterized in that, the first seal comprises an O-ring coupled to a backup ring, said backup ring being interposed between said O-ring and the rotating member, and being formed of less deformable material with respect to the material constituting the O-ring. said caliper comprising: - a cylinder, forming a cylindrical wall and a bottom wall transverse to the cylindrical wall; - a piston, forming a side wall and a thrust wall substantially transverse to the side wall and opposite to the bottom wall of the cylinder, - a cylinder, forming a cylindrical wall and a bottom wall transverse to the cylindrical wall; - a piston, forming a side wall and a thrust wall substantially transverse to the side wall and opposite to the bottom wall of the cylinder, wherein said bottom wall forms an inner surface facing towards the piston and an opposite outer surface facing opposite to the piston, wherein the piston is accommodated within the cylinder, and the side wall of the piston is adapted to slide within the cylindrical wall of the cylinder, wherein the piston is configured to be biased by a pressurized brake fluid injectable within the cylinder, to affect at least one of said pads against one of said brake disc friction surfaces, along a thrust direction substantially parallel to the axial direction (A-A), said caliper further comprising a parking-braking system which comprises a rotating member; said rotating member being rotatably accommodated within a rotation housing formed in the bottom wall of the cylinder so that the rotating member is rotatable about a rotation axis substantially parallel to the axial direction (A-A), wherein the cylinder defines a first annular housing and a second annular housing made in the bottom wall, said first and second annular housings (13, 14) extending into the bottom wall in a direction transverse to the axial direction (A-A) and leading into the rotation housing, said second annular housing being distinct from said first annular housing, and being positioned in a direction opposite to the inner surface of the bottom wall with respect to said first annular housing, wherein the first annular housing accommodates a first seal, and the second annular housing accommodates a second seal, and wherein the first and second seals (15, 16) are configured to act between said rotating member and said bottom wall of the cylinder to be fluid-tight; characterized in that, the first seal comprises an O-ring coupled to a backup ring, said backup ring being interposed between said O-ring and the rotating member, and being formed of less deformable material with respect to the material constituting the O-ring.