YouTube Premium (formerly Music Key and YouTube Red) is a subscription service offered by the American video platform YouTube. The service provides ad-free access to content across the service, as well as access to premium YouTube Originals programming produced in collaboration with the site's creators, ability to download videos and listen background playback of videos on mobile devices, and access to the music streaming service, YouTube Music, along with other benefits. It has over 125 million subscribers.

The service was originally launched on November 14, 2014, as Music Key, offering advertisement-free streaming of music videos from participating labels on YouTube and Google Play Music. The service was then revised and relaunched as YouTube Red on October 21, 2015, expanding its scope to offer advertisement-free access to all YouTube videos, as opposed to just music.

YouTube announced the rebranding of the service as YouTube Premium on May 17, 2018, alongside the return of a separate, YouTube Music subscription service. Later in the year, it was reported that YouTube was planning to make some of the original content associated with the service available on an ad-supported basis.

The service was first unveiled in November 2014 as Music Key, serving as a collaboration between YouTube and Google Play Music, and meant to succeed the latter's own "All Access" service. Music Key offered ad-free playback of music videos from participating labels hosted on YouTube, as well as background and offline playback of music videos on mobile devices from within the YouTube app. The service also included access to Google Play Music All Access, which provides ad-free audio streaming of a library of music. Alongside Music Key, Google also introduced tighter integration between Play Music and YouTube's apps, including the sharing of music recommendations, and access to YouTube's music videos from within the Play Music app. Music Key was not YouTube's first foray into premium content, having launched film rentals in 2010, and premium, subscription-based channels in 2013.

During its invite-only beta, Music Key faced mixed reception due to the limited scope of the offering; YouTube's chief business officer Robert Kyncl explained that his daughter was confused over why videos of songs from Frozen were not "music" in the scope of the service, and thus not advertisement-free. These concerns and others led to a revamping of the Music Key concept to create YouTube Red.

YouTube Red was officially unveiled on October 21, 2015. Unlike Music Key, YouTube Red was designed to provide ad-free streaming to all videos, rather than just music content. This shift required YouTube to seek permission from its content creators and rights holders to allow their content to be part of the ad-free service; under the new contract terms, partners would receive a share of the total revenue from YouTube Red subscriptions, as determined by how much their content is viewed by subscribers.

YouTube also sought to compete against sites such as Netflix, Amazon Prime Video and Hulu by offering original content (YouTube Originals) as part of the subscription service, leveraging prominent YouTube personalities in combination with professional producers. Robert Kyncl acknowledged that many of YouTube's prominent personalities had built their followings and created content while operating on a "shoestring budget", but he maintained that "in order to scale up, it takes a different kind of enterprise, a different kind of skill set" such as story-telling and "showrunning". Prominent YouTube personality PewDiePie, who was involved in one of the planned originals for the service, explained that the service was meant to mitigate profit loss from the use of ad blocking.

On May 18, 2016, YouTube Red and YouTube Music launched in Australia and New Zealand, the first countries to gain access to the service outside the United States. On August 3, 2016, YouTube Red support was added to the YouTube Kids app. On December 6, 2016, YouTube Red expanded to South Korea.