A rear light for motor vehicles comprising: a first cup-shaped body which has the inner surface mirror finished so as to reflect the incident light; - at least one main light source which is located close to the bottom of said first cup-shaped body, and is structured so as to emit light when electrically powered; and a front lenticular body which is made of transparent or semitransparent material, and is arranged so as to cover the mouth of said first cup-shaped body, so that the light emitted by said at least one main light source passes therethrough; the rear light further comprising: - a second cup-shaped body which is rigidly fixed within the first cup-shaped body, above said at least one main light source, with its concavity facing the lenticular body; and - a first additional light source which is arranged close to the bottom of the second cup-shaped body and is structured so as to emit light when electrically powered; characterised by also comprising: - a substantially funnel-shaped light-guiding sleeve which is made of photoconductive material and is fitted on the mouth of the first cup-shaped body, underneath the lenticular body, so that the inner annular rim of the same funnel-shaped light-guiding sleeve is fitted on the second cup-shaped body, outside the latter, and so that the outer annular rim of the same funnel-shaped light-guiding sleeve is arranged above the peripheral rim of the first cup-shaped body and completely surrounds the lenticular body; and - a second additional light source which is fixed on the second cup-shaped body so as to face the inner annular rim of the funnel-shaped light-guiding sleeve, is structured so as to emit light when electricity powered, and is oriented so that the light emitted by the second additional light source penetrates within the light-guiding sleeve through the inner annular rim and propagates to the outer annular rim of the same light-guiding sleeve. - a second cup-shaped body which is rigidly fixed within the first cup-shaped body, above said at least one main light source, with its concavity facing the lenticular body; and - a first additional light source which is arranged close to the bottom of the second cup-shaped body and is structured so as to emit light when electrically powered; - a substantially funnel-shaped light-guiding sleeve which is made of photoconductive material and is fitted on the mouth of the first cup-shaped body, underneath the lenticular body, so that the inner annular rim of the same funnel-shaped light-guiding sleeve is fitted on the second cup-shaped body, outside the latter, and so that the outer annular rim of the same funnel-shaped light-guiding sleeve is arranged above the peripheral rim of the first cup-shaped body and completely surrounds the lenticular body; and - a second additional light source which is fixed on the second cup-shaped body so as to face the inner annular rim of the funnel-shaped light-guiding sleeve, is structured so as to emit light when electricity powered, and is oriented so that the light emitted by the second additional light source penetrates within the light-guiding sleeve through the inner annular rim and propagates to the outer annular rim of the same light-guiding sleeve.