The Eurovision Song Contest (French: Concours Eurovision de la chanson), sometimes abbreviated to ESC and often known simply as Eurovision, is an international songwriting competition organised annually by the European Broadcasting Union (EBU), featuring participants representing primarily European countries. Each participating country submits an original song to be performed on live television and radio, transmitted to national broadcasters via the EBU's Eurovision and Euroradio networks, with competing countries then casting votes for the other countries' songs to determine a winner.

Based on the Sanremo Music Festival held in Italy since 1951, Eurovision has been held annually since 1956 (apart from 2020), making it the longest-running annual international televised music competition and one of the world's longest-running television programmes. Active members of the EBU, as well as invited associate members, are eligible to compete, and as of 2021, 52 countries have participated at least once. Each participating broadcaster sends one original song of three minutes duration or less to be performed live by a singer or group of up to six people aged 16 or older. Each country awards two sets of 1–8, 10 and 12 points to their favourite songs, based on the views of an assembled group of music professionals and the country's viewing public, with the song receiving the most points declared the winner. Other performances feature alongside the competition, including a specially-commissioned opening and interval act and guest performances by musicians and other personalities, with past acts including Cirque du Soleil, Madonna and the first performance of Riverdance. Originally consisting of a single evening event, the contest has expanded as new countries joined (including countries outside of Europe, such as Australia), leading to the introduction of relegation procedures in the 1990s, and eventually the creation of semi-finals in the 2000s. As of 2021, Germany has competed more times than any other country, having participated in all but one edition, while Ireland holds the record for the most victories, with seven wins in total.

Traditionally held in the country which won the preceding year's event, the contest provides an opportunity to promote the host country and city as a tourist destination. Thousands of spectators attend each year, and journalists are present to cover all aspects of the contest, including rehearsals in venue, press conferences with the competing acts, and other related events and performances in the host city. Alongside the generic Eurovision logo, a unique theme and slogan is typically developed for each event. The contest has aired in countries across all continents, and has been available online via the official Eurovision website since 2000. Eurovision ranks among the world's most watched non-sporting events every year, with hundreds of millions of viewers globally, and performing at the contest has often provided artists with a local career boost and in some cases long-lasting international success. Several of the best-selling music artists in the world have competed in past editions, including ABBA, Celine Dion, Julio Iglesias, Cliff Richard and Olivia Newton-John, and some of the world's best-selling singles have received their first international performance on the Eurovision stage.

While having gained popularity with the viewing public in both participating and non-participating countries, the contest has also been the subject of criticism for its artistic quality as well as a perceived political aspect to the event. Concerns have been raised regarding political friendships and rivalries between countries potentially having an impact on the results. Controversial moments have included participating countries withdrawing at a late stage, censorship of broadcast segments by broadcasters, and political events impacting participation. Likewise, the contest has also been criticised for an over-abundance of elaborate stage shows at the cost of artistic merit. Eurovision has, however, gained popularity for its kitsch appeal, its musical span of ethnic and international styles, as well as emergence as part of LGBT culture, resulting in a large, active fanbase and an influence on popular culture. The popularity of the contest has led to the creation of several similar events, either organised by the EBU or created by external organisations, and several special events have been organised by the EBU to celebrate select anniversaries or as a replacement due to cancellation.