Siem is a surname. Notable people with the surname include:
Charlie Siem (born 1986), British-Norwegian violinist Kjetil Siem (born 1960), Norwegian businessperson, journalist, author and sports official Kristian Siem (born 1949), Norwegian businessman Martin Siem (1915–1996), Norwegian businessperson Mary Alice Siem, American activist Ole Siem (1882–1979), Norwegian naval officer, businessman and politician Sasha Siem (born 1984), British-Norwegian singer-songwriter and composer Sunniva Siem (born 1969), Norwegian physicist
See also Security information and event management Siems Sihem