The oyster fishery is 1 of the most important coastal fisheries in Mexico. Management is based on a minimum legal size of 80 mm and several seasonal bans that vary along the coast of the Gulf of Mexico. We describe the gonad development cycle of Crassostrea virginica (Gmelin 1791) along the Mexican coast of the Gulf of Mexico for 5 lagoons for the years 2000 and 2004, between latitudes 21°41′16.75″ N and 18°23′51.08″ N. Significant differences in duration and intensity were observed among reproductive stages associated with different environmental conditions. Gametogenesis and mature stages correlated positively with temperature and total chlorophyll, respectively. Spawning correlated negatively with salinity in both years. Maturity correlated positively with total chlorophyll levels. The reproductive stages varied from seasonal, a few months, to continuous throughout the year. Recovery, expressed as the number of organisms in postspawning and resting stages, was fast for populations that presented constant gametogenesis and spawning, with less than 50% of the population in postspawning and resting stages. Environmental fluctuations in total chlorophyll are the regulating factors for gametogenic activity, rather than latitudinal temperature variations. This makes monitoring environmental conditions in the lagoons or gonad development a necessity to predict reproduction and recruitment for proper management of the oyster resource.