 Argentina: Used by the Argentine military before they were replaced.

 Australia: Australian Defence Force previously used Australian and American-made M1s from the 1960s to the 1990s.
Replaced by the Australian-made M91 PASGT helmet in the 1990s.

 Austria: Used by the Austrian Army after it was reformed in 1955 with 30,000 M1s supplied by the US.
Copies made in 1958 known as Stahlhelm 2 (M.58) with another made in the 1970s with a German-made helmet suspension, all made by Ulbrichts Witwe.

 Belgium: Used Ulbrichts-made M1 helmets.

 Brazil: Formerly used US and Brazilian-made M1s for its military.

 British Hong Kong: Formerly used by the Royal Hong Kong Police Force.

 Bolivia: Used US, Brazilian, and South Korean-made M1s before being removed from service.

 Canada: Used until the 1990s, when it was replaced by the CG634 helmet.

 Chile: Formerly used by the Chilean military with liners made by Baselli Hnos.

 China, Republic of: Used in the Second Sino-Japanese War and in the Chinese Civil War.
Used by Taiwan until the 1990s.

 China, People's Republic of: Used captured M1 helmets from the Chinese Nationalist Army during the Chinese Civil War.
Extremely few, if any, saw service beyond that conflict.

 Costa Rica: Formerly used US-made M1 helmets.

 Cuba: Used in Cuban military until Bastista was deposed, replaced by Warsaw Pact-made helmets.

 Denmark: Used Ulbrichts-made M1 helmets under the designation of Staalhjelm model 48 (m/48).

 Ecuador: Formerly in use by the Ecuadorian military.

 El Salvador: Provided by the US in the 1970s as part of military aid, now replaced by PASGT.

 Greece: Adopted by the Greek Army in 1952.

 Haiti: Used by former Haitian military.

 Honduras: Formerly used by Honduran military after signing the Rio Treaty.

 Iran: Formerly used by the Imperial Iranian Army.
Used by the Islamic Republic of Iran's army, until retirement, however it occasionally still sees some limited use.

 Israel: Formerly used by the Israeli military, supplied by the UK, France, and the United States.
Some M1s used have a combination of US and Israeli parts.

 Lebanon: Used American-made M1s.

 Mexico: Formerly used by the Mexican military.

 Malaysia:Used by Malaysian Army and Royal Malaysia Police.

 New Zealand: Used by the New Zealand Army from the 1960s all the way to 2000s, mostly using US and South Korean-made M1s.

 Netherlands: Used Ulbrichts-made M1 helmets.

 Nicaragua: The Guardia Nacional de Nicaragua used M1 helmets supplied by the United States 1954-1979.

 Norway: Used Ulbrichts-made M1 helmets.

 Pakistan:Formerly used by the Pakistan Army.
Now GIDs ballistic helmets are in use.

 Paraguay: Adopted the M1 after signing the Rio Treaty.

 Peru: Formerly used M1 helmets supplied by the US.
Some obtained from Israel and West Germany.

 Philippines: Formerly used M1 helmet in the Armed Forces of the Philippines.
Some reserve stocks for training of the recruits.

 Saudi Arabia: Formerly used M1 helmets supplied via South Korea and Taiwan.

 Singapore: Formerly used by the Singaporean military from the late 1950s with inner liners made locally.
Used up until the mid-1980s, when they began to be gradually replaced, and finally phased out, by a similar helmet to the US PASGT helmet, in the 1990s.

 Spain: Used M1s made from America and Europe, modified for marine and paratrooper forces.

 South Vietnam: The standard helmet of the South Vietnamese military from 1955 up until the fall of the country to North Vietnam in 1975, all throughout the Vietnam War.

 Turkey: Used by the Turkish military, most made locally.

 United States: Formerly used by the United States Air Force as the M3 and later, the M5, helmet for flak protection.
Formerly used by the US military from the 1940s to the 80s, replaced by the PASGT.

 Venezuela: Used by the Venezuelan military, now replaced.
Majority made in the US and South Korea.

 West Germany: Formerly used by the West German army, helmets made by F. W. Quist Company.
The West German M-56 Stahlhelm was a direct copy of the U.S. M1 helmet.
It was properly called "zweiteiliger Stahlhelm" (two-piece steel helmet
 Argentina: Used by the Argentine military before they were replaced.
 Australia: Australian Defence Force previously used Australian and American-made M1s from the 1960s to the 1990s. Replaced by the Australian-made M91 PASGT helmet in the 1990s.
 Austria: Used by the Austrian Army after it was reformed in 1955 with 30,000 M1s supplied by the US. Copies made in 1958 known as Stahlhelm 2 (M.58) with another made in the 1970s with a German-made helmet suspension, all made by Ulbrichts Witwe.
 Belgium: Used Ulbrichts-made M1 helmets.
 Brazil: Formerly used US and Brazilian-made M1s for its military.
 British Hong Kong: Formerly used by the Royal Hong Kong Police Force.
 Bolivia: Used US, Brazilian, and South Korean-made M1s before being removed from service.
 Canada: Used until the 1990s, when it was replaced by the CG634 helmet.
 Chile: Formerly used by the Chilean military with liners made by Baselli Hnos.
 China, Republic of: Used in the Second Sino-Japanese War and in the Chinese Civil War. Used by Taiwan until the 1990s.
 China, People's Republic of: Used captured M1 helmets from the Chinese Nationalist Army during the Chinese Civil War. Extremely few, if any, saw service beyond that conflict.
 Costa Rica: Formerly used US-made M1 helmets.
 Cuba: Used in Cuban military until Bastista was deposed, replaced by Warsaw Pact-made helmets.
 Denmark: Used Ulbrichts-made M1 helmets under the designation of Staalhjelm model 48 (m/48).
 Ecuador: Formerly in use by the Ecuadorian military.
 El Salvador: Provided by the US in the 1970s as part of military aid, now replaced by PASGT.
 Greece: Adopted by the Greek Army in 1952.
 Haiti: Used by former Haitian military.
 Honduras: Formerly used by Honduran military after signing the Rio Treaty.
 Iran: Formerly used by the Imperial Iranian Army. Used by the Islamic Republic of Iran's army, until retirement, however it occasionally still sees some limited use.
 Israel: Formerly used by the Israeli military, supplied by the UK, France, and the United States. Some M1s used have a combination of US and Israeli parts.
 Lebanon: Used American-made M1s.
 Mexico: Formerly used by the Mexican military.
 Malaysia:Used by Malaysian Army and Royal Malaysia Police.
 New Zealand: Used by the New Zealand Army from the 1960s all the way to 2000s, mostly using US and South Korean-made M1s.
 Netherlands: Used Ulbrichts-made M1 helmets.
 Nicaragua: The Guardia Nacional de Nicaragua used M1 helmets supplied by the United States 1954-1979.
 Norway: Used Ulbrichts-made M1 helmets.
 Pakistan:Formerly used by the Pakistan Army. Now GIDs ballistic helmets are in use.
 Paraguay: Adopted the M1 after signing the Rio Treaty.
 Peru: Formerly used M1 helmets supplied by the US. Some obtained from Israel and West Germany.
 Philippines: Formerly used M1 helmet in the Armed Forces of the Philippines. Some reserve stocks for training of the recruits.
 Saudi Arabia: Formerly used M1 helmets supplied via South Korea and Taiwan.
 Singapore: Formerly used by the Singaporean military from the late 1950s with inner liners made locally. Used up until the mid-1980s, when they began to be gradually replaced, and finally phased out, by a similar helmet to the US PASGT helmet, in the 1990s.
 Spain: Used M1s made from America and Europe, modified for marine and paratrooper forces.
 South Vietnam: The standard helmet of the South Vietnamese military from 1955 up until the fall of the country to North Vietnam in 1975, all throughout the Vietnam War.
 Turkey: Used by the Turkish military, most made locally.
 United States: Formerly used by the United States Air Force as the M3 and later, the M5, helmet for flak protection. Formerly used by the US military from the 1940s to the 80s, replaced by the PASGT.
 Venezuela: Used by the Venezuelan military, now replaced. Majority made in the US and South Korea.
 West Germany: Formerly used by the West German army, helmets made by F. W. Quist Company. The West German M-56 Stahlhelm was a direct copy of the U.S. M1 helmet. It was properly called "zweiteiliger Stahlhelm" (two-piece steel helmet
M1 helmet