Lighting and/or signalling device for the automotive sector, comprising: at least two separately powered and activated light sources (16',16") comprising an upstream light source and a downstream light source (16") relative to a prevailing propagation direction (X-X) of respective emitted light beams, - an upstream light guide, provided with an upstream light input portion, facing the upstream light source so as to receive in input the light beam produced by the latter and to emit it in output through an upstream light output wall, - a downstream light guide provided with a downstream light input portion, facing the downstream light source (16") so as to receive the light beam produced by the latter and emit it in output through a downstream light output wall, - said upstream and downstream light guides (24,36) being arranged side by side in series with each other with respect to said prevailing propagation direction(X-X), so that the light beam emitted by the upstream light output wall is channelled through an intermediate wall of the downstream light guide and by this is reflected and transmitted through the downstream light output wall, characterised in that the upstream light guide is shaped so as to transfer, by total internal reflection, the light beam emitted by the upstream light source from the upstream light output wall to the intermediate wall of the downstream light guide, characterized in that the intermediate wall comprises at least one input window counter-shaped relative to a corresponding output window of the upstream light output wall, wherein said input window is substantially perpendicular to the prevailing propagation direction (X-X), wherein the intermediate wall further comprises at least one downstream collimation wall shaped to collimate the rays produced by the downstream light source and to collimate them towards the downstream light output wall. at least two separately powered and activated light sources (16',16") comprising an upstream light source and a downstream light source (16") relative to a prevailing propagation direction (X-X) of respective emitted light beams, - an upstream light guide, provided with an upstream light input portion, facing the upstream light source so as to receive in input the light beam produced by the latter and to emit it in output through an upstream light output wall, - a downstream light guide provided with a downstream light input portion, facing the downstream light source (16") so as to receive the light beam produced by the latter and emit it in output through a downstream light output wall, - said upstream and downstream light guides (24,36) being arranged side by side in series with each other with respect to said prevailing propagation direction(X-X), so that the light beam emitted by the upstream light output wall is channelled through an intermediate wall of the downstream light guide and by this is reflected and transmitted through the downstream light output wall, - an upstream light guide, provided with an upstream light input portion, facing the upstream light source so as to receive in input the light beam produced by the latter and to emit it in output through an upstream light output wall, - a downstream light guide provided with a downstream light input portion, facing the downstream light source (16") so as to receive the light beam produced by the latter and emit it in output through a downstream light output wall, - said upstream and downstream light guides (24,36) being arranged side by side in series with each other with respect to said prevailing propagation direction(X-X), so that the light beam emitted by the upstream light output wall is channelled through an intermediate wall of the downstream light guide and by this is reflected and transmitted through the downstream light output wall, characterised in that the upstream light guide is shaped so as to transfer, by total internal reflection, the light beam emitted by the upstream light source from the upstream light output wall to the intermediate wall of the downstream light guide, characterized in that the intermediate wall comprises at least one input window counter-shaped relative to a corresponding output window of the upstream light output wall, wherein said input window is substantially perpendicular to the prevailing propagation direction (X-X), wherein the intermediate wall further comprises at least one downstream collimation wall shaped to collimate the rays produced by the downstream light source and to collimate them towards the downstream light output wall.