Bathos (UK: /ˈbeɪθɒs/ BAY-thoss; Ancient Greek: βάθος, lit. "depth") is a literary term, first used in this sense in Alexander Pope's 1727 essay "Peri Bathous", to describe an amusingly failed attempt at presenting artistic greatness. Bathos has come to refer to rhetorical anticlimax, an abrupt transition from a lofty style or grand topic to a common or vulgar one, occurring either accidentally (through artistic ineptitude) or intentionally (for comic effect). Intentional bathos appears in satirical genres such as burlesque and mock epic. "Bathos" or "bathetic" is also used for similar effects in other branches of the arts, such as musical passages marked ridicolosamente. In film, bathos may appear in a contrast cut intended for comic relief or be produced by an accidental jump cut.

As a term for the combination of the very high with the very low, bathos was introduced by Alexander Pope in his essay Peri Bathous, Or the Art of Sinking in Poetry (1727). On the one hand, Pope's work is a parody in prose of Longinus's Peri Hupsous (On the Sublime), in that he imitates Longinus's system for the purpose of ridiculing contemporary poets, but, on the other, it is a blow Pope struck in an ongoing struggle against the "dunces."

The nearest model for Pope's essay is the Treatise of the Sublime by Boileau of 1712. Pope admired Boileau, but one of Pope's literary adversaries, Leonard Welsted, had issued a "translation" of Longinus in 1726 that was merely a translation of Boileau. Because Welsted and Pope's other foes were championing this "sublime", Pope commented upon and countered their system with his Peri Bathos in the Swift-Pope-Gay-Arbuthnot Miscellanies. Whereas Boileau had offered a detailed discussion of all the ways in which poetry could ascend or be "awe-inspiring", Pope offers a lengthy schematic of the ways in which authors might "sink" in poetry, satirizing the very men who were allied with Ambrose Philips. Pope and Philips had been adversaries since the publication of Pope's Odes, and the rivalry broke down along political lines. According to Pope, bathos can be most readily applicable to love making after two years of marriage which is clearly in binary opposition to the sublime but is no less political. Edmund Burke was believed to be particularly charmed by Pope's articulation of love after marriage, inspiring Burke's essay A Philosophical Enquiry into the Origin of Our Ideas of the Sublime and Beautiful (1756).

One example of Pope's style and satire is in his description of sinking in painting. In the commonplace Academic hierarchic ranking of pictorial genres, still life ranked the lowest. However, Pope describes how it might fall and, with the single word "stiffen", evokes the unnatural deadness that is a mark of failure even in this "low" genre:

Many Painters who could never hit a Nose or an Eye, have with Felicity copied a Small-Pox, or been admirable at a Toad or a Red-Herring. And seldom are we without Genius's for Still Life, which they can work up and stiffen with incredible Accuracy. ("Peri Bathous" vi).

In chapters X and XI, Pope explains the comic use of the tropes and figures of speech.

Although Pope's manual of bad verse offers numerous methods for writing poorly, of all these ways to "sink", the method that is most remembered now is the act of combining very serious matters with very trivial ones. The radical juxtaposition of the serious with the frivolous does two things. First, it violates decorum, or the fittingness of the subject, and, second, it creates humor with an unexpected and improper juxtaposition.

Since Pope's day, the term "bathos", perhaps because of confusion with "pathos", has been used for art forms, and sometimes events, where something is so pathetic as to be humorous.