| Country | Constitution |
| Grenada | 19 December 1973 |
| Guam | Organic Act of Guam, 1 August 1950 |
| Guatemala | 31 May 1985, effective 14 January 1986; suspended 25 May 1993; reinstated 5 June 1993; amended November 1993 |
| Guernsey | unwritten; partly statutes, partly common law and practice |
| Guinea | 7 May 2010 (Loi Fundamentale) |
| Guinea-Bissau | 16 May 1984; amended several times |
| Guyana | 6 October 1980 |
| Haiti | approved March 1987 note: suspended June 1988 with most articles reinstated March 1989; constitutional government ousted in a military coup in September 1991, although in October 1991 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 |
| Heard Island and McDonald Islands | void |
| Holy See (Vatican City) | Fundamental Law promulgated by Pope JOHN PAUL II 26 November 2000, effective 22 February 2001 (replaced the first Fundamental Law of 1929) |
| Honduras | 11 January 1982, effective 20 January 1982; amended many times |
| Hong Kong | The Basic Law, approved March 1990 by China's National People's Congress, is Hong Kong's charter |
| Hungary | 25 April 2011, effective 1 January 2012 |
| Iceland | 16 June 1944, effective 17 June 1944; amended many times |
| India | 26 January 1950; amended many times |
| Indian Ocean | void |
| Indonesia | August 1945; abrogated by Federal Constitution of 1949 and Provisional Constitution of 1950, restored 5 July 1959; series of amendments concluded in 2002 |
| Iran | 2-3 December 1979; revised 1989 note: the revision in 1989 expanded powers of the presidency and eliminated the prime ministership |
| Iraq | ratified 15 October 2005 (subject to review by the Constitutional Review Committee and a possible public referendum) |