A flexible lighting device, including: - a channel-shaped elongate housing with a web portion and two side portions extending along said elongate housing sidewise of said web portion, wherein each said side portion includes, facing inwardly of the channel shape of said elongate housing, a proximal groove extending along said elongate housing sidewise of said web portion - electrically conductive line means extending along said web portion internally of the channel shape of said elongate housing, and - a light radiation source assembly including: - i) a support board having a back surface facing said web portion of said elongate housing with respective electrically conductive line means making electrical contact with said electrically conductive line means and a front surface facing outwardly of the channel shape of said elongate housing, said support board having lateral sides extending into said proximal grooves in said side portions of said elongate housing; and - ii) at least one electrically-powered light radiation source on said front surface, said at least one light radiation source in electrical contact with said respective electrically conductive line means, characterized in that each side portion includes, facing inwardly of the channel shape of said elongate housing, a distal groove extending along said elongate housing distally of said proximal groove, the flexible lighting device further including: - at least one electrical connector having insertion formations insertable plug-like into said distal grooves in said side portions of said elongate housing, said connector being provided with electrical contact parts for making electrical contact with said electrically conductive line means extending along said web portion internally of said channel shape of the elongate housing. - a channel-shaped elongate housing with a web portion and two side portions extending along said elongate housing sidewise of said web portion, wherein each said side portion includes, facing inwardly of the channel shape of said elongate housing, a proximal groove extending along said elongate housing sidewise of said web portion - electrically conductive line means extending along said web portion internally of the channel shape of said elongate housing, and - a light radiation source assembly including: - i) a support board having a back surface facing said web portion of said elongate housing with respective electrically conductive line means making electrical contact with said electrically conductive line means and a front surface facing outwardly of the channel shape of said elongate housing, said support board having lateral sides extending into said proximal grooves in said side portions of said elongate housing; and - ii) at least one electrically-powered light radiation source on said front surface, said at least one light radiation source in electrical contact with said respective electrically conductive line means, - i) a support board having a back surface facing said web portion of said elongate housing with respective electrically conductive line means making electrical contact with said electrically conductive line means and a front surface facing outwardly of the channel shape of said elongate housing, said support board having lateral sides extending into said proximal grooves in said side portions of said elongate housing; and - ii) at least one electrically-powered light radiation source on said front surface, said at least one light radiation source in electrical contact with said respective electrically conductive line means, - at least one electrical connector having insertion formations insertable plug-like into said distal grooves in said side portions of said elongate housing, said connector being provided with electrical contact parts for making electrical contact with said electrically conductive line means extending along said web portion internally of said channel shape of the elongate housing.