word | | Constitution |
| March | United States | 17 September 1787, effective 4 March 1789 |
| Mariana | Northern Mariana Islands | Constitution of the Commonwealth of the Northern Mariana Islands effective 1 January 1978; Covenant Agreement fully effective 4 November 1986 |
| May | Argentina | 1 May 1853; amended many times starting in 1860 |
| May | Austria | 1 October 1920; revised 1929; reinstated 1 May 1945; revised many times; note - during the period 1 May 1934-1 May 1945 there was a fascist (corporative) constitution in place |
| May | Cameroon | approved by referendum 20 May 1972; adopted 2 June 1972; revised January 1996; amended April 2008 |
| May | Cyprus | ... when the Turkish Cypriots declared independence in 1983; a new constitution for the "TRNC" passed by referendum on 5 May 1985, although the "TRNC" remains unrecognized by any country other than Turkey |
| May | Egypt | 11 September 1971; amended 22 May 1980, 25 May 2005, and 26 March 2007; note - constitution suspended by the military caretaker government 13 February 2011 and a new provisional constitution adopted 30 ... |
| May | Eritrea | adopted 23 May 1997, but has not yet been fully implemented |
| May | Germany | 23 May 1949, known as Basic Law; became constitution of the united Germany 3 October 1990 |
| May | Guatemala | 31 May 1985, effective 14 January 1986; suspended 25 May 1993; reinstated 5 June 1993; amended November 1993 |
| May | Guinea | 7 May 2010 (Loi Fundamentale) |
| May | Guinea-Bissau | 16 May 1984; amended several times |
| May | Haiti | ... military government claimed to be observing the constitution; returned to constitutional rule in October 1994; constitution, while technically in force between 2004-2006, was not enforced; returned to constitutional rule in May 2006 |