The Sixth Amendment of the Constitution of Ireland ensured that certain adoption orders would not be found to be unconstitutional because they had not been made by a court. It was effected by the Sixth Amendment of the Constitution (Adoption) Act, 1979 which was approved by referendum on 5 July 1979 and signed into law on 3 August 1979 of the same year.
No adoption of a person taking effect or expressed to take effect at any time after the coming into operation of this Constitution under laws enacted by the Oireachtas and being an adoption pursuant to an order made or an authorisation given by any person or body of persons designated by those laws to exercise such functions and powers was or shall be invalid by reason only of the fact that such persons or body of persons was not a judge or a court appointed or established as such under this Constitution.
In 1977 it came to light that for technical reasons child adoption orders made by An Bord Uchtála (the Adoption Board) might be found to be unconstitutional because they were not made by a court or judge. An amendment was therefore required to put the validity of these orders beyond question. The Sixth Amendment was introduced by a Fianna Fáil government but was supported by every other major political party and not controversial. It was put to a referendum on the same day as the similarly uncontroversial Seventh Amendment which dealt with university constituencies for the election of the Senate. The Sixth Amendment was approved almost unanimously on a low turnout with 601,694 (99.0%) votes in favour and 6,265 (1.0%) against.