Code of Alabama
Chapter 15 - Special Elections.
Section 17-15-1 - When and for What Offices Held.

Special elections are to be held in the following cases:
(1) When a vacancy occurs in the office of senator or representative in the Legislature, when the Legislature will be in session prior to the next general election for that office.
(2) When a vacancy occurs in the office of representative in the Congress of the United States, by which the state may be deprived of its full representation at any time Congress will be in session prior to the next general election for that office.
(3) Whenever any general or special election for members of the Legislature or for representatives in Congress is not held.
(4) When any vacancy occurs in any state or county office filled by election of the people not otherwise provided for by the Constitution of Alabama of 1901, or laws of this state.
(5) In such other cases as are or may be provided for by law.