Upper class in modern societies is the social class composed of people who hold the highest social status, usually are the wealthiest members of class society, and wield the greatest political power. According to this view, the upper class is generally distinguished by immense wealth which is passed on from generation to generation. Prior to the 20th century, the emphasis was on aristocracy, which emphasized generations of inherited noble status, not just recent wealth.

Because the upper classes of a society may no longer rule the society in which they are living, they are often referred to as the old upper classes, and they are often culturally distinct from the newly rich middle classes that tend to dominate public life in modern social democracies. According to the latter view held by the traditional upper classes, no amount of individual wealth or fame would make a person from an undistinguished background into a member of the upper class as one must be born into a family of that class and raised in a particular manner to understand and share upper class values, traditions, and cultural norms. The term is often used in conjunction with terms like upper-middle class, middle class, and working class as part of a model of social stratification.