Vinciguerria attenuata, commonly known as the slender lightfish, is a small species of ray-finned fish in the family Phosichthyidae, found in deep water in warmer parts of the Atlantic, the Indian and Pacific Oceans.

Vinciguerria attenuata is a moderately elongate fish with a tapering body growing to a length of about 45 mm (1.8 in).

The eyes are slightly tubular and set close together, giving vision both upwards and sideways.

There are photophores (light-producing organs) on the lower half of the head and in rows on the underside of the fish.

The dorsal surface of the body is dark, the flanks are silvery and the fins are colourless, without streaks.