Knopf (also spelt Knopff) is a German surname meaning "button", and may refer to:

• Adolph Knopf (1882–1966), American geologist
• Alfred A. Knopf Sr. (1892–1984), American publisher
• Edwin H. Knopf (1899–1981), American film producer, director and screenwriter
• Eleanora Knopf (1883–1974), American geologist
• Heinrich Knopf (1839–1875), German luthier
• Jim Knopf, computer specialist
• Maike-Katrin Knopf (born 1959), German footballer
• Philip Knopf (1847–1920), member of the United States House of Representatives from Illinois
• Rainer Knopff, Canadian political scientist
• Sigard Adolphus Knopf (1857–1940), German-American physician

• Fernand Khnopff, Belgian artist