Annual production of soles in Bardawil Lagoon was gradually decreased from 343 MT in 2008 to be 161 MT in 2016. This work aims to investigate reproductive biology of the common sole, Solea solea, to provide biological base for management of its fisheries in Bardawil Lagoon, North Sinai, Egypt. Monthly samples of S. solea were collected from the commercial catch in different landing sites of the lagoon during 2016-2017. The length-weight relation was found as W= 0.0055 L^3.171, W= 0.0047 L^2.334 and W= 0.0048 L^3.2215 for males, females and combined sexes respectivly. Generally, low values of condition factors were recorded in June and July, and the highest value was recorded in December. Gonado-Somatic Index (GSI) of females showed that S. solea spawn during November, December and January since GSI peaked in these months (6.77, 8.72 and 8.48 % respectively). The lowest value of GSI of females was recorded in August (1.09%). Overall sex ratio (males : females) was 1: 1.99 during the period of study. Lengths at first sexual maturity (L_m) were determined as 19.8 and 20.1 cm for males and females respectively. The absolute fecundity (F) was increasing with the fish length and described by a power equation: F= 7.0918 L^3.6374. The relative fecundity gradually increased from 8092.5 to 36680.6 eggs per cm (average 20766.6 eggs/ cm). To protect and maintain the stock of common sole in Bardawil Lagoon, it is recommended to ban using fishing nets of illegal mesh sizes and other destructive fishing methods which catch small fish sizes, length at first capture should be larger than length at first sexual maturity (> 20.1 cm) and ban fishing nets targeting soles during its spawning season (from November to January).