word | | Constitution |
| October | Wallis and Futuna | 4 October 1958 (French Constitution) |
| official | Belgium | ... 1831; amended many times; revised 14 July 1993 to create a federal state; in 1967 an official Dutch version of the constitution was adopted; in 1991 an official German version of the ... |
| officially | Switzerland | revision of Constitution of 1874 approved by the Federal Parliament 18 December 1998, adopted by referendum 18 April 1999, officially entered into force 1 January 2000 |
| Omani | Oman | ... the royal succession, provides for a prime minister, bars ministers from holding interests in companies doing business with the government, establishes a bicameral legislature, and guarantees basic civil liberties for Omani citizens |
| ombudsman | Cape Verde | 25 September 1992; a major revision on 23 November 1995 substantially increased the powers of the president; a 1999 revision created the position of national ombudsman (Provedor de Justica) |
| ongoing | Somalia | 25 August 1979, presidential approval 23 September 1979 note: the formation of transitional governing institutions, known as the Transitional Federal Government, is currently ongoing |
| operates | Libya | ... the Declaration of the Establishment of the People's Authority; note - the Transitional National Council, recognized by the UN in September 2011 as the legitimate interim government, operates under a temporary constitution |
| Order | Akrotiri | Sovereign Base Areas of Akrotiri and Dhekelia Order in Council 1960, effective 16 August 1960, functions as a basic legal document |
| Order | Anguilla | Anguilla Constitutional Order 1 April 1982; amended 1990 |
| Order | Cayman Islands | The Cayman Islands Constitution Order 2009, 6 November 2009 |
| Order | Dhekelia | Sovereign Base Areas of Akrotiri and Dhekelia Order in Council 1960, effective 16 August 1960, functions as a basic legal document |
| order | European Union | none note: the EU legal order, although based on a series of treaties, has often been described as "constitutional" in nature; the Treaty on European Union (TEU), as modified by the Lisbon ... |