C

• Expatriate units and formations of Czechoslovakia (2 C, 6 P)

E

• Eagle Squadrons (1 C, 11 P)
• Expatriate units and formations of Poland (3 C, 5 P)

F

• Flight of the Wild Geese (2 C, 11 P)
• Flying Tigers (2 C, 10 P)
• Force Publique (3 C, 3 P)
• Foreign regiments in British Service (2 C, 12 P)
• Foreign units of Nazi Germany (3 C, 4 P)
• Foreign volunteers in the Second Boer War (16 P)
• French expatriate units and formations (5 C, 9 P)

G

• Ghilman (5 C, 17 P)

I

• International Brigades (2 C, 40 P, 1 F)
• Irish regiments (12 C, 7 P)

J

• Jewish Legion (1 C, 4 P)

N

• Non-British Royal Air Force personnel of World War II (7 C, 31 P)

R

• Expatriate units and formations of Romania (2 C, 4 P)

S

• Foreign volunteers in Serbian armies (8 P)
• Foreign volunteers in the Spanish Civil War (2 C, 2 P)
• Spanish Legion (1 C, 8 P)
• Swiss mercenaries (3 C, 52 P)
• Expatriate units and formations in the Syrian civil war (1 C, 8 P)

U

• Pro-Ukraine foreign volunteer units in the Russo-Ukrainian War (3 C)

V

• Varangian Guard (2 C, 9 P)

W

• Volunteers in the Winter War (1 C, 24 P)

• List of foreign volunteers

0–9

• 1st Canadian Regiment
• 1st Regiment Greek Light Infantry
• 1st South African Infantry Brigade
• 2nd Canadian Regiment
• 7th Air Escadrille
• 22nd Territorial Rifle Corps
• 24th Territorial Rifle Corps
• 27th Jäger Battalion (Finland)
• 29th Territorial Rifle Corps
• 32 Battalion (South Africa)
• 88th Separate Rifle Brigade

A

• Abuzar Brigade
• Arab Liberation Army
• Armenian battalions
• Aviazione Legionaria

B

• Battaglione Azad Hindoustan
• Bavarian Auxiliary Corps
• Belgian Legion
• Blue Legion
• Boer foreign volunteers
• British Legion (1860)
• Bulgarian Legion

C

• Catalan Company
• Chinese in the Russian Revolution and in the Russian Civil War
• Chinese Labour Corps
• Condor Legion
• Congolese National Liberation Front
• Corpo Truppe Volontarie
• Corsican Guard

D

• De Watteville's Regiment
• Dodecanese Regiment

E

• Eagle Squadrons

F

• Finnish Artillery Regiment
• Finnish Guards' Rifle Battalion
• Finnish Infantry Regiment 200
• Flying Regiment 19, Finnish Air Force
• Flying Tigers
• Foreign enlistment in the American Civil War
• Foreign fighter
• Foreign fighters in the Russo-Ukrainian War
• Mexican Expeditionary Air Force

G

• Gardes Suisses (France)
• Greek Battalion of Balaklava
• Greek Volunteer Guard
• Greek Volunteer Legion

H

• Harvard Surgical Unit
• Hohenlohe Regiment
• Huimin Company
• Hungarian volunteers in the Winter War

I

• Indian Labour Corps
• International Brigades
• International Brigades order of battle
• International Legion
• Irish military diaspora
• Islamic Legion

J

• Operation Jedburgh
• Military history of Jewish Americans

K

• KATCOM
• Korean Augmentation to the United States Army

L

• 1st Laotian Parachute Battalion
• Lodge–Philbin Act

M

• Mahal (Israel)
• List of members of the British Free Corps
• Mickiewicz Legion
• List of militaries that recruit foreigners
• Murmansk Legion

N

• No. 10 (Inter-Allied) Commando
• No. 164 Squadron RAF
• Non-British personnel in the RAF during the Battle of Britain

O

• Ohrana

P

• Papal Zouaves
• People's Volunteer Army
• Pohjan Pojat
• Polish Air Forces in France and Great Britain
• Polish Legion in Finland

R

• Regiment de Meuron
• Royal Yugoslav Air Force Detachment

S

• Saint Patrick's Battalion
• Saqaliba
• Scythian archers
• Serb volunteers in the Greek War of Independence
• Slavic Legion
• Soldatenhandel
• Soviet Volunteer Group
• Spanish Legion
• Swedish Brigade
• Swedish Volunteer Battalion
• Swedish Volunteer Company
• Swedish Volunteer Corps
• Foreign fighters in the Syrian civil war

U

• Ukrainian interbrigade company Taras Shevchenko

V

• 1st Vietnamese Parachute Battalion
• 3rd Vietnamese Parachute Battalion
• 5th Vietnamese Parachute Battalion
• Volunteer Regiment of Buda

W

• Walloon Guards