Kalk may refer to:
- Kalk, Cologne, a borough of Cologne, Germany
- Chemische Fabrik Kalk, a former German chemical company
- USS Kalk (DD-170), a US destroyer during World War I
- Stanton Frederick Kalk (1894–1917), for whom the USS Kalk is named
- Kalk, Poland
- Abbreviation for Kalkaska, Michigan
- Kalk, an Afrikaans word meaning limestone