Kieler Sportvereinigung Holstein von 1900 e.V., simply as KSV Holstein or Kieler SV Holstein, commonly known as Holstein Kiel, is a German association football and sports club based in the city of Kiel, Schleswig-Holstein. From the 1900s through the 1960s, the club was one of the most dominant sides in northern Germany. Some notable honors from that period include the German football championship in 1912, and being vice-champions 1910 and 1930. Holstein also won six regional titles and finished as runners-up another nine times. They remained a first-division side until the formation of the Bundesliga in 1963. They will make their debut in the Bundesliga in the 2024-25 season after gaining promotion from the 2. Bundesliga in 2024.

Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 246,243 (2021).