Missouri Revised Statutes Title XI. Education and Libraries § 160.051. Public school system established--child attains age five, when--board shall provide free instruction for children between ages of five and six years--literacy programs--summer school for prekindergartners

1. A system of free public schools is established throughout the state for the gratuitous instruction of persons between the ages of five and twenty-one years. Any child whose fifth birthday occurs before the first day of August shall be deemed to have attained the age of five years at the commencement of the school year beginning in that calendar year or at the commencement of the summer school session immediately prior to the school term beginning in the school year beginning in that calendar year, whichever is earlier, for the purpose of apportioning state school funds and for all other purposes.

2. Public schools may establish family literacy programs for children of all ages and their families.

3. The department of elementary and secondary education shall not use school for kindergarten pupils in the summer preceding such pupils' regular fall starting date as an element of the standards of the Missouri school improvement program.