Fossen is a Norwegian surname which can refer to these people:

• Aksel Fossen (born 29 November 1919), Norwegian politician for the Labour Party
• Erling Fossen (October 23, 1963) Norwegian nonfiction writer and former NRK-show host
• Hildegunn Fossen (born April 16, 1969) retired Norwegian biathlete
• Michael Fossen (born September 22, 1949) American playwright, television writer, and novelist
• Steve Fossen, Founding Member & Original Bassist for Heart (band)
• Thor I. Fossen (born 3 January 1963), Norwegian professor, author and founder of the company Marine Cybernetics
• Tor Røste Fossen (born 19 June 1940), Norwegian former football player and coach

• Saiho-ji Zen Garden
• Saihoun
• Saihō-ji (Kyoto)
• Saiichi Maruya
• Saiichi Sugiyama
• Sai-I-Gu
• Sai I Gu
• Sai-in
• Saiin
• Sai-in (disambiguation)
• Saiin (disambiguation)
• Saiin (priestess)
• Saiin (princess)
• Saiin Station
• Sai-in Station
• Sai-in Station and Sai Station
• Sai-in Temple (Nara)
• Sai-in (Western Precinct)
• Saijanjoki
• Saija Varjus
• Sai-ji
• Saiji
• Saijida al-Rishawi
• Saijida Mubarak Atrous al-Rishawi
• Saijo, Ehime