Artificial light at night (ALAN) disrupts insect behaviour at a massive scale, with moths and other nocturnal insects drawn to light sources where they circle exhaustedly, fail to reproduce, and die prematurely. Research estimates that a single streetlight kills thousands of insects nightly. Beyond direct mortality, light pollution disrupts insect navigation, mating, foraging, and migration. The welfare status of insects is uncertain but growing evidence of nociception in some species warrants precautionary consideration. Pollinator disruption from ALAN affects agricultural productivity and ecosystem function, linking insect welfare to broader environmental welfare concerns. Mitigation includes switching to amber/red-spectrum LED lighting (less attractive to insects), motion-activated lighting, shielded fixtures directing light downward, and dark sky preserves. Growing dark sky movement has achieved policy traction in several European countries with lighting regulations.