The ruling comes after a parent complained that her child in grade one, a class for six-year-olds, had deep bruises after a beating by a teacher.
Linah Pfungwa said her daughter had been punished for failing to have her reading book signed by guardians as proof she had done her homework.
The constitutional court will have to confirm the judgement.
The BBC's Shingai Nyoka in the capital, Harare, says if upheld, it would transform the way parents have disciplined their children for centuries in the southern African country.
Some parents are criticising the ruling, while rights groups says it is long overdue, she says.