BuzzFeed Unsolved (also known as simply Unsolved) is a documentary entertainment web series created by Ryan Bergara for BuzzFeed that ran from February 4, 2016, to November 19, 2021. It first appeared on the YouTube channel BuzzFeed Blue and was later given its own flagship channel BuzzFeed Unsolved Network.The show was split into two alternating themes, with each season seeing Bergara and co-host Shane Madej discussing either unsolved crimes in BuzzFeed Unsolved True Crime or investigating alleged haunted locations and demonic possessions in BuzzFeed Unsolved Supernatural. While the topics of discussion were often morbid, most episodes were presented in a comedic manner, cutting between Bergara's voiceover of the episode's topic and comedic discussion with Madej. The show was filmed primarily in the United States, with some episodes filmed in separate locations in the UK and Mexico. Most episodes were followed by a question and answer episode, entitled BuzzFeed Unsolved Postmortem, where Bergara and Madej answered questions sent in by viewers about the week's episode.

The show became one of BuzzFeed's most watched shows, which led the series to start streaming on Hulu and Amazon Prime in 2018. Prior to the premiere of season 8, BuzzFeed renewed the show for a 9th season, which appeared in late 2018. In 2019, the 10th season premiered in March and the 11th season premiered in September. In late 2019, Bergara and Madej started their own digital production company, Watcher Entertainment, with Worth It's Steven Lim; however, the two continued BuzzFeed Unsolved with a 12th season in March 2020.

BuzzFeed Unsolved True Crime concluded with its 8th and final season in July 2021, and the 7th and final season of BuzzFeed Unsolved Supernatural started in October 2021 and wrapped in November. There are a total of fifteen seasons. Due to the COVID-19 pandemic, Supernatural skipped 2020 and has one less season than True Crime because production was unable to secure haunted locations to visit under quarantine. The final episode was followed up by a behind-the-scenes documentary BuzzFeed Unsolved: The Making of the Final Investigation on 24 November 2021.The spiritual successor to BuzzFeed Unsolved Supernatural is Ghost Files, a documentary entertainment web series by Watcher Entertainment that was first released on September 23, 2022. The successor to BuzzFeed Unsolved True Crime is Mystery Files, which was released on May 19, 2023.