Aesthetics (also esthetics in American English) is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed through judgments of taste.

Aesthetics covers both natural and artificial sources of experiences and how we form a judgment about those sources. It considers what happens in our minds when we engage with objects or environments such as viewing visual art, listening to music, reading poetry, experiencing a play, watching a fashion show, movie, sports or even exploring various aspects of nature. The philosophy of art specifically studies how artists imagine, create, and perform works of art, as well as how people use, enjoy, and criticize art. Aesthetics considers why people like some works of art and not others, as well as how art can affect moods or even our beliefs. Both aesthetics and the philosophy of art try to find answers for what exactly is art, artwork, or what makes a good art.

Scholars in the field have defined aesthetics as "critical reflection on art, culture and nature". In modern English, the term "aesthetic" can also refer to a set of principles underlying the works of a particular art movement or theory (one speaks, for example, of a Renaissance aesthetic).