A lighting device, such as for example a LED flexible module, includes an elongated profiled body having a mouth portion, a first and a second lateral sides arranged sidewise of the mouth portion and a web side opposed the mouth portion. The profiled body includes a light-permeable portion, extending between the mouth portion and the first lateral side, and a light-impermeable portion extending between the second lateral side and the web side. A light radiation source assembly including a support member with one or more electrically powered light radiation sources is arranged at the mouth portion with the light radiation source(s) facing the light-permeable portion, whereby light radiation is directed towards the first lateral side for emission from the lighting device.