Knopp is a surname. Notable people with the name include:
- Alex Knopp (born 1947), American professor and former politician
- Fay Honey Knopp (1918–1995), American Quaker minister, peace and civil rights advocate
- Gary Knopp (1957–2020), American politician
- Guido Knopp (born 1948), German journalist and author
- Konrad Knopp (1882–1957), German mathematician working on generalized limits and complex functions
- Marvin Knopp (1933–2011), American mathematician who worked primarily in number theory
- Otto A. Knopp (1877–1946), German-American innovator of the standard testing transformer
- Tim Knopp (born 1965), American politician and businessman
