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

See also

• Security information and event management
• Siems
• Sihem