Vaporwave is a microgenre of electronic music, a visual art style, and an Internet meme that emerged in the early 2010s and became well-known in 2015. It is defined partly by its slowed-down, chopped and screwed samples of smooth jazz, 1970s elevator music, R&B, and lounge music from the 1980s and 1990s; similar to synthwave. The surrounding subculture is sometimes associated with an ambiguous or satirical take on consumer capitalism and pop culture, and tends to be characterized by a nostalgic or surrealist engagement with the popular entertainment, technology and advertising of previous decades. Visually, it incorporates early Internet imagery, late 1990s web design, glitch art, anime, stylized Ancient Greek or Roman sculptures, 3D-rendered objects, and cyberpunk tropes in its cover artwork and music videos.

Vaporwave originated as an ironic variant of chillwave, evolving from hypnagogic pop as well as similar retro-revivalist and post-Internet motifs that had become fashionable in underground digital music and art scenes of the era, such as Tumblr's seapunk. The style was pioneered by producers such as James Ferraro, Daniel Lopatin and Ramona Langley, who each used various pseudonyms. After Langley's album Floral Shoppe (2011) established a blueprint for the genre, the movement built an audience on sites Last.fm, Reddit and 4chan while a flood of new acts, also operating under online pseudonyms, turned to Bandcamp for distribution.

Following the wider exposure of vaporwave in 2012, a wealth of subgenres and offshoots emerged, such as future funk, mallsoft and hardvapour, although most have waned in popularity. The genre also intersected with fashion trends such as streetwear and various political movements. Since the mid-2010s, vaporwave has been frequently described as a "dead" genre. The general public came to view vaporwave as a facetious Internet meme, a notion that frustrated some producers who wished to be recognized as serious artists. Many of the most influential artists and record labels associated with vaporwave have since drifted into other musical styles. Later in the 2010s, the genre spurred a revival of interest in Japanese ambient music and city pop and in the 2020s with the spread of its latest subgenre, Frutiger Aero, sharing its name with the graphical style.

Vaporwave is a hyper-specific subgenre, or "microgenre", that is both a form of electronic music and an art style; however, it is sometimes suggested to be primarily a visual medium. The genre is defined largely by its surrounding subculture, with its music inextricable from its visual accoutrements. Academic Laura Glitsos writes, "In this way, vaporwave defies traditional music conventions that typically privilege the music over the visual form." Musically, vaporwave reconfigures dance music from the 1980s and early 1990s through the use of chopped and screwed techniques, repetition, and heavy reverb. It is composed almost entirely from slowed-down samples and its creation requires only the knowledge of rudimentary production techniques. However, some artists like Dan Mason create vaporwave music from scratch.

The name derives from "vaporware", a term for commercial software that is announced but never released. It builds upon the satirical tendencies of chillwave and hypnagogic pop, while also being associated with an ambiguous or ironic take on consumer capitalism and technoculture. Critic Adam Trainer writes of the style's predilection for "music made less for enjoyment than for the regulation of mood", such as corporate stock music for infomercials and product demonstrations. Academic Adam Harper described the typical vaporwave track as "a wholly synthesised or heavily processed chunk of corporate mood music, bright and earnest or slow and sultry, often beautiful, either looped out of sync and beyond the point of functionality."

Adding to its dual engagement with musical and visual art forms, vaporwave embraces the Internet as a cultural, social, and aesthetic medium. The visual aesthetic (often stylized as "ＡＥＳＴＨＥＴＩＣＳ", with fullwidth characters) incorporates early Internet imagery, late 1990s web design, glitch art, and cyberpunk tropes, as well as anime, Greco-Roman statues, and 3D-rendered objects. VHS degradation is another common effect seen in vaporwave art. Generally, artists limit the chronology of their source material between Japan's economic flourishing in the 1980s and the September 11 attacks or dot-com bubble burst of 2001 (some albums, including Floral Shoppe, depict the intact Twin Towers on their covers).

Vaporwave originated on the Internet in the early 2010s as an ironic variant of chillwave and as a derivation of the work of hypnagogic pop artists such as Ariel Pink and James Ferraro, who were also characterized by the invocation of retro popular culture. It was one of many Internet microgenres to emerge in this era, alongside witch house, seapunk, shitgaze, cloud rap, and others. Vaporwave coincided with a broader trend involving young artists whose works drew from their childhoods in the 1980s.

"Chillwave" and "hypnagogic pop" were coined at virtually the same time, in mid-2009, and were considered interchangeable terms. Like vaporwave, they engaged with notions of nostalgia and cultural memory. Among the earliest hypnagogic acts to anticipate vaporwave was Matrix Metals and his album Flamingo Breeze (2009), which was built on synthesizer loops. Around the same time, Daniel Lopatin (Oneohtrix Point Never) uploaded a collection of plunderphonics loops to YouTube surreptitiously under the alias sunsetcorp. These clips were taken from his audio-visual album Memory Vague (June 2009). Washed Out's "Feel It All Around" (June 2009), which slowed down the 1983 Italian dance song "I Want You" by Gary Low, exemplified the "analog nostalgia" of chillwave that vaporwave artists sought to reconfigure.