Chapter XV Amendment of the Constitution
§ 161. The right to initiate amendment of the Constitution rests with not less than one-fifth of the membership of the Riigikogu and with the President of the Republic.
Amendment of the Constitution shall not be initiated, nor shall the Constitution be amended, during a state of emergency or a state of war.
§ 162. Chapter I “General Provisions” and Chapter XV “Amendment of the Constitution” of the Constitution may be amended only by a referendum.
§ 163. The Constitution shall be amended by an Act which has been passed by:
1) a referendum;
2) two successive memberships of the Riigikogu; 3) the Riigikogu, as a matter of urgency.
A bill to amend the Constitution shall be debated for three readings in the Riigikogu, in which the interval between the first and second readings shall be not less than three months, and the interval between the second and third readings shall be not less than one month. The manner in which the Constitution is to be amended shall be decided at the third reading.
§ 164. A three-fifths majority of the membership of the Riigikogu is required to submit a bill to amend the Constitution to a referendum. The referendum shall be held not earlier than three months after the passage of a resolution to this effect by the Riigikogu.
§ 165. In order to amend the Constitution by two successive memberships of the Riigikogu, a bill to amend the Constitution must be supported by a majority of the membership of the Riigikogu.
If the bill to amend the Constitution which receives the support of the majority of the preceding membership of the Riigikogu is passed by the succeeding Riigikogu, unamended, on its first reading and with a three-fifths majority, then the Constitution Amendment Act is passed.
§ 166. A resolution to consider a bill to amend the Constitution as a matter of urgency shall be passed by a four-fifths majority of the Riigikogu. In this case, the Constitution Amendment Act shall be passed by a two-thirds majority of the membership of the Riigikogu.
§ 167. The Constitution Amendment Act shall be proclaimed by the President of the Republic and shall enter into force on the date specified therein, but not earlier than three months from the date of proclamation.
§ 168. An amendment to the Constitution regarding the same issue shall not be initiated within one year after the rejection of a corresponding bill by a referendum or by the Riigikogu.