Esmark is a surname. Notable people with the surname include:
Birgitte Esmark (1841–1897), Norwegian malacologist Jens Esmark (1763–1839), Danish-Norwegian mineralogist, study of glaciers Lars Mathias Hille Esmark (1908–1998), Norwegian civil servant Morten Thrane Esmark (1801-1882), Norwegian priest and mineralogist
See also Esmark Inc., an American company founded in 2008, operating mainly in the steel industry Esmark Glacier, glacier in South Georgia Island Esmarkbreen, glacier in Svalbard JBS USA, successor of former holding company Esmark