Wisconsin constitution
Article X: education
As amended april 1972.

The legislature shall provide by law for the establishment of district schools, which shall be as nearly uniform as practicable; and such schools shall be free and without charge for tuition to all children between the ages of 4 and 20 years; and no sectarian instruction shall be allowed therein; but the legislature by law may, for the purpose of religious instruction outside the district schools, authorize the release of students during regular school hours.