A description of the courtship and mating behavior ofBemisia tabaci(Gennadius) is presented. Upon emergence, both sexes were clear winged and sexually immature. They matured during the next 24 h and their wings were coated with wax. Newly emerged males were attracted to 1-d-old females and sometimes initiated courtship that rarely persisted. Males between 10 and 24 h old readily initiated courtship but failed to complete antennation. Newly emerged adult females were not attractive to males for about 10 h. Females accepted courting males 20–24 h after emergence. The precopulatory, copulatory, and postcopulatory behaviors, including the time spent at each step, are described for mature adults. Unsuccessful sexual encounters included male and female rejection, male–male interference, and misdirected sexual behavior. A comparison of the sexual behavior ofB. tabaciandTrialeurodes vaporariorum(Westwood) suggests thatB. tabaci, likeT. vaporariorum, may use a sex pheromone.