Naïve art is usually defined as visual art that is created by a person who lacks the formal education and training that a professional artist undergoes (in anatomy, art history, technique, perspective, ways of seeing). When this aesthetic is emulated by a trained artist, the result is sometimes called primitivism, pseudo-naïve art, or faux naïve art.

Unlike folk art, naïve art does not necessarily derive from a distinct popular cultural context or tradition; indeed, at least in the advanced economies and since the Printing Revolution, awareness of the local fine art tradition has been inescapable, as it diffused through popular prints and other media. Naïve artists are aware of "fine art" conventions such as graphical perspective and compositional conventions, but are unable to fully use them, or choose not to. By contrast, outsider art (art brut) denotes works from a similar context but which have only minimal contact with the mainstream art world.

Naïve art is recognized, and often imitated, for its childlike simplicity and frankness. Paintings of this kind typically have a flat rendering style with a rudimentary expression of perspective. One particularly influential painter of "naïve art" was Henri Rousseau (1844–1910), a French Post-Impressionist who was discovered by Pablo Picasso.

The definition of the term, and its "borders" with neighbouring terms such as folk art and outsider art, has been a matter of some controversy. Naïve art is a term usually used for the forms of fine art, such as paintings and sculptures, made by a self-taught artist, while objects with a practical use come under folk art. But this distinction has been disputed. Another term that may be used, especially of paintings and architecture, is "provincial", essentially used for work by artists who had received some conventional training, but whose work unintentionally falls short of metropolitan or court standards.

While naïve art was often viewed (prior to the twentieth century) as outsider art produced by those without formal (or little) training or degrees, it is now a fully recognized art genre, represented in art galleries and academies worldwide.

The characteristics of naïve art have an awkward relationship to the formal qualities of painting, especially not respecting the three rules of the perspective (such as defined by the Progressive Painters of the Renaissance):

The results are:

Simplicity rather than subtlety are all supposed markers of naïve art. It has, however, become such a popular and recognizable style that many examples could be called pseudo-naïve.