Arsenal Football Club is a professional football club based in Islington, London, England. Arsenal plays in the Premier League, the top flight of English football. The club has won 13 league titles (including one unbeaten title), a record 14 FA Cups, two League Cups, 16 FA Community Shields, the League Centenary Trophy, one European Cup Winners' Cup, and one Inter-Cities Fairs Cup.

Arsenal was the first club from the South of England to join the Football League, in 1893, and they reached the First Division in 1904. Relegated only once, in 1913, they continue the longest streak in the top division, and have won the second-most top-flight matches in English football history. In the 1930s, Arsenal won five League Championships and two FA Cups, and another FA Cup and two Championships after the war. In 1970–71, they won their first League and FA Cup Double. Between 1989 and 2005, they won five League titles and five FA Cups, including two more Doubles. They completed the 20th century with the highest average league position.

Herbert Chapman, who changed the fortunes of Arsenal forever, won the club its first silverware, and his legacy led the club to dominate the 1930s decade; Chapman, however, died of pneumonia in 1934, aged 55. He helped introduce the WM formation, floodlights, and shirt numbers; he also added the white sleeves and brighter red to the club's jersey. Arsène Wenger is the longest-serving manager and won the most trophies. He won a record seven FA Cups, and his title-winning team set an English record for the longest top-flight unbeaten league run at 49 games between 2003 and 2004, receiving the nickname The Invincibles.

In 1886 munitions workers at the Royal Arsenal in Woolwich founded the club as Dial Square. In 1913, the club crossed the city to Arsenal Stadium in Highbury, becoming close neighbours of Tottenham Hotspur, and creating the North London derby. In 2006, they moved to the nearby Emirates Stadium. With an annual revenue of €388m in the 19–20 season, Arsenal was estimated to be worth US$2.68 billion by Forbes, making it the world's seventh most valuable club, while it is one of the most followed on social media. The motto of the club has long been Victoria Concordia Crescit, Latin for "Victory Through Harmony".

For much of Arsenal's history, their home colours have been bright red shirts with white sleeves and white shorts, though this has not always been the case. The choice of red is in recognition of a charitable donation from Nottingham Forest, soon after Arsenal's foundation in 1886. Two of Dial Square's founding members, Fred Beardsley and Morris Bates, were former Forest players who had moved to Woolwich for work. As they put together the first team in the area, no kit could be found, so Beardsley and Bates wrote home for help and received a set of kit and a ball. The shirt was redcurrant, a dark shade of red, and was worn with white shorts and socks with blue and white hoops. In 1933, Herbert Chapman, wanting his players to be more distinctly dressed, updated the kit, adding white sleeves and changing the shade to a brighter pillar box red. Two possibilities have been suggested for the origin of the white sleeves. One story reports that Chapman noticed a supporter in the stands wearing a red sleeveless sweater over a white shirt; another was that he was inspired by a similar outfit worn by the cartoonist Tom Webster, with whom Chapman played golf. Regardless of which story is true, the red and white shirts have come to define Arsenal and the team have worn the combination ever since, aside from two seasons. The first was 1966–67, when Arsenal wore all-red shirts; this proved unpopular and the white sleeves returned the following season. The second was 2005–06, the last season that Arsenal played at Highbury, when the team wore commemorative redcurrant shirts similar to those worn in 1913, their first season in the stadium; the club reverted to their normal colours at the start of the next season. In the 2008–09 season, Arsenal replaced the traditional all-white sleeves with red sleeves with a broad white stripe.

Arsenal's first ever silverware was won as the Royal Arsenal in 1890. The Kent Junior Cup, won by Royal Arsenal's reserves, was the club's first trophy, while the first team's first trophy came three weeks later when they won the Kent Senior Cup. Their first national senior honour came in 1930, when they won the FA Cup. The club enjoyed further success in the 1930s, winning another FA Cup and five Football League First Division titles. Arsenal won their first league and cup double in the 1970–71 season and twice repeated the feat, in 1997–98 and 2001–02, as well as winning a cup double of the FA Cup and League Cup in 1992–93.