The population ecology of luciferids has been scarcely studied. This study examined the distribution and population parameters of Belzebub faxoni and Lucifer typus in the western Gulf of Mexico. Samples were collected using a Bongo net at 82 sampling stations during three periods (July, January, and October–November). Abundance data of species were subjected to a regression tree analysis to determine the main factors affecting their distribution. In addition, total length data of individuals were fitted to a logistic equation to estimate the size at first maturity. Food availability was the key factor affecting the distribution of B. faxoni, which exhibited its highest abundance over the inner shelf. In contrast, L. typus avoided low salinity waters (<35.9 psu), and its highest densities were found over the slope and oceanic areas. The sex ratio in B. faxoni was always biased towards females, but L. typus showed variable sex proportions. Several hypotheses attempting to explain these disparities are discussed. Size structure in B. faxoni favored small individuals in summer, the reproduction peak. In contrast, the L. typus population was always dominated by large individuals, probably transported by currents from the main hatching sites. Size at first maturity was higher in L. typus (females: 8.16 mm; males: 8.63 mm) than in B. faxoni (females: 6.53 mm; males: 6.74 mm). Information here provided may help to better understand the population dynamics of these species.