Alt-pop, short for alternative pop, is a broad style of Pop music which combines chart pop conventions with an underground sensibility drawing from more modern types of Indie Pop like the orchestrated Chamber Pop and Indietronica, as well as the more serious Art Pop. Though stylistically diverse, alt-pop errs towards more minimal arrangements that put an emphasis on deep or quiet vocals, and frequently features a darker, dreamier, and more downbeat tone from other pop. The genre has also drawn from other contemporary popular trends, particularly the synth stylings of Electropop, the vocal delivery of Contemporary R&B, the atmospheric downbeat style of Alternative R&B and often Downtempo oriented sound. Lyrically, alt-pop tends to focus on more personal or autobiographical topics, touching on pop mainstays like love, heartbreak, and adolescence as well as darker topics like alienation and depression. The idea of concept albums has become one of the most recurrent aspects of the scene, where artists tend to develop their own narratives, sometimes playing a persona.

The term "alternative pop" has been around since the rise of Alternative Rock to popularity in the late 1980s, but the distinctive alt-pop sound would not emerge until the early 2010s. Early alt-pop remained much closer to its indie pop roots, with crossover hits like "Somebody That I Used to Know" by Gotye which established the genre's more minimal and contemplative yet poppy and accessible sound. In the following years, singer-songwriter Lana Del Rey would release her debut album Born to Die and Lorde would follow her successful single "Royals" with Pure Heroine, and these artists would establish the genre as a phenomenon in its own right, buoyed by a young and dedicated fanbase on social media (particularly Tumblr). Their style moved further away from the genre's indie pop roots, dipping into more orchestrated and more electronic sound palettes to create eclectic and diverse pop albums. Producer Jack Antonoff (of fun., another early alt-pop pioneer) would be an important figure in shaping this sound, and would even bring some elements of alt-pop to his collaborations with more mainstream pop artists.

In the following years, a new generation would come up inspired by this movement, shifting the sound even further into electronic territory. In particular, singer Billie Eilish would come to represent a sound sometimes called "dark pop", blending low, breathy vocals with thick, bassy synths and modern electronic percussion, as well as a darker or even horror-themed atmosphere. This new wave would also include artists with stronger contemporary R&B influence like Melanie Martinez, Troye Sivan and Halsey, as well as the more organic sounds and live instrumentation of crossover artists from the intimate Bedroom Pop scene like Clairo and Rex Orange County. Though some of these artists have achieved mainstream success through traditional outlets like labels and radio play, others have remained independent and primarily release and promote their music through social media and online streaming services, challenging the traditional image of a "pop star".