Utilitarianism is a moral theory that determines the morality of actions based on their consequences. Specifically, an action is morally right if it produces the greatest amount of happiness or well-being for the greatest number of people. Utilitarianism aims to maximize overall well-being in society but this can sometimes come at the cost of disadvantaging certain groups. While utilitarianism focuses on aggregate well-being, other theories like Kantianism emphasize moral duty and universal principles over consequences.