| Country | Constitution |
| Hungary |  18 August 1949, effective 20 August 1949; revised 19 April 1972; 18 October 1989; and 1997 note: 18 October 1989 revision ensured legal rights for individuals and constitutional checks on the authority of the prime minister and also established the principle of parliamentary oversight; 1997 amendment streamlined the judicial system |
| 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 in 1989 note: the revision in 1989 expanded powers of the presidency and eliminated the prime ministership |
| Iraq | ratified on 15 October 2005 (subject to review by the Constitutional Review Committee and a possible public referendum ) |
| Ireland | adopted 1 July 1937 by plebiscite; effective 29 December 1937 |
| Isle of Man | unwritten; note - The Isle of Man Constitution Act of 1961 does not embody the unwritten Manx Constitution |
| Israel | no formal constitution; some of the functions of a constitution are filled by the Declaration of Establishment (1948), the Basic Laws of the parliament (Knesset), and the Israeli citizenship law; note - since May 2003 the Constitution, Law, and Justice Committee of the Knesset has been working on a draft constitution |
| Italy | passed 11 December 1947, effective 1 January 1948; amended many times |
| Jamaica | 6 August 1962 |
| Jan Mayen | void |
| Japan | 3 May 1947 |
| Jersey | unwritten; partly statutes, partly common law and practice |
| Jordan | 1 January 1952; amended many times |
| Kazakhstan | first post-independence constitution adopted 28 January 1993; new constitution adopted by national referendum 30 August 1995 |
| Kenya | 12 December 1963; amended as a republic 1964; reissued with amendments 1979, 1982, 1986, 1988, 1991, 1992, 1997, 2001; note - a new draft constitution was defeated by popular referendum in 2005 |
| Kiribati | 12 July 1979 |