A better knowledge of the reproductive biology of Loligo duvauceli squid, such as its sex ratio, sexual maturation, and reproductive seasonality is fundamental for establishing effective fishery management measures to ensure the fishery is sustainable. Samples of Loligo duvauceli were collected monthly for one fishing season during September 2014 to April 2015 at Attaka fishing harbor in the Gulf of Suez. A total of 759 individuals (434 males, 268 females, and 57 not recognized) in size range of 3.5 to 29.5 cm dorsal mantle length (DML) were used for this study. The sex ratio of males: females was 1.6:1.0. Females outnumbered males only in February. However, males were dominant in the rest of the fishing season. Four maturity stages for both sexes were recognized. Monthly variations in maturity stages and maturity indices showed that the spawning season extends from April to October (spring to early autumn) for females, while males from April to September (spring to late autumn). Length at first sexual maturity indicated that the females attain maturity at smaller DML than males. The mean length at maturity for this species was 14.8 and 17.5cm DML for females and males, respectively.