A lighting device for vehicles, comprising at least one LED light source and an optical system for collecting and distributing, according to a desired photometric profile, the light produced by said LED light source; the optical system comprising a light guide formed by a block of material normally pervious to light; wherein, in combination: i)- the block of material normally pervious to light is shaped in order to define a solid wedge-shaped three-dimensional element, delimited among an upper face thereof, a lower face thereof, two opposite lateral surfaces thereof, at least a front face thereof defining a first longitudinal end thereof and at least a rear face thereof, defining a second longitudinal end thereof, opposed to the first longitudinal end; ii)- the lateral surfaces are curved and converge towards each other on the side of said second longitudinal end, so that the block of material normally pervious to light widens fanning out towards the first end; said opposite curved lateral surfaces being configured in order to cause a total, or at least partial, internal reflection of the light within the block of material normally pervious to light; iii)- the at least one rear face is arranged facing said at least one LED light source and is provided with, or defines, a concavity, which surrounds, at least partially, said at least one LED light source and which is delimited by a first arc-shaped curved surface configured to collect at least part of the light emitted by said at least one LED light source within the block of material normally pervious to light; iv)- the block of material normally pervious to light is crossed by at least one perforation made transversally to said upper and lower faces and interposed between the front face and the rear face; the at least one perforation being delimited internally by a first optical surface arranged facing the front face, and by a second optical surface arranged facing the rear face, the at least one perforation being configured to define an air lens interposed between the concavity of the at least one rear face and the at least one front face; characterized in that v) - the upper face and/or the lower face is arranged obliquely with respect to a horizontal plane, so that both the upper and lower faces converge towards each other either vi)- on the side of said second longitudinal end causing a progressive decrease of a thickness, measured vertically, of the block of material normally pervious to light towards the second longitudinal end thereof; or vii)- on the side of said first longitudinal end causing a progressive decrease of a thickness, measured vertically, of the block of material normally pervious to light towards the first longitudinal end thereof. i)- the block of material normally pervious to light is shaped in order to define a solid wedge-shaped three-dimensional element, delimited among an upper face thereof, a lower face thereof, two opposite lateral surfaces thereof, at least a front face thereof defining a first longitudinal end thereof and at least a rear face thereof, defining a second longitudinal end thereof, opposed to the first longitudinal end; ii)- the lateral surfaces are curved and converge towards each other on the side of said second longitudinal end, so that the block of material normally pervious to light widens fanning out towards the first end; said opposite curved lateral surfaces being configured in order to cause a total, or at least partial, internal reflection of the light within the block of material normally pervious to light; iii)- the at least one rear face is arranged facing said at least one LED light source and is provided with, or defines, a concavity, which surrounds, at least partially, said at least one LED light source and which is delimited by a first arc-shaped curved surface configured to collect at least part of the light emitted by said at least one LED light source within the block of material normally pervious to light; iv)- the block of material normally pervious to light is crossed by at least one perforation made transversally to said upper and lower faces and interposed between the front face and the rear face; the at least one perforation being delimited internally by a first optical surface arranged facing the front face, and by a second optical surface arranged facing the rear face, the at least one perforation being configured to define an air lens interposed between the concavity of the at least one rear face and the at least one front face; v) - the upper face and/or the lower face is arranged obliquely with respect to a horizontal plane, so that both the upper and lower faces converge towards each other either vi)- on the side of said second longitudinal end causing a progressive decrease of a thickness, measured vertically, of the block of material normally pervious to light towards the second longitudinal end thereof; or vii)- on the side of said first longitudinal end causing a progressive decrease of a thickness, measured vertically, of the block of material normally pervious to light towards the first longitudinal end thereof.