Weight Watchers (NYSE: WTW) is an international company that offers various dieting products and services to assist weight loss and maintenance. Founded in 1963 by Brooklyn homemaker Jean Nidetch, it now^[update] operates in about 30 countries around the world, generally under names that are local translations of "Weight Watchers".

Weight Watchers encourages members to select a goal weight that results in a body mass index generally accepted as healthy (20 to 25), although a member may also establish a goal weight outside of that range after providing a doctor's note to that effect. In the United States, in order to join Weight Watchers, one must weigh at least 5 pounds (2.3 kg) more than the minimum weight for his or her height.

Once a member reaches his or her goal weight, he or she starts a maintenance period. For the following six weeks, the member gradually increases his or her food intake until the member no longer loses or gains weight. If, at the end of six weigh-ins during the maintenance period, the member weighs in within 2 pounds (0.91 kg) of his or her goal weight, he or she becomes a "Lifetime" member. A Lifetime member may attend meetings free of charge as long as he or she weighs in at least once per calendar month and, at any weigh-in, does not weigh more than 2 pounds (0.91 kg) more than his or her goal weight. If the member weighs more than 2 pounds (0.91 kg) over the goal weight at a weigh-in, he or she will be charged the weekly fee until he or she again obtains a weight within the target range. As long as a Lifetime member weighs in each month and stays within the target range, there is no fee for attending meetings, and the member may attend for the rest of his or her life. Unlike with new members, there is never a registration fee for Lifetime members, even if they regain weight or fail to weigh in every calendar month.