Archbishop Charles Scicluna is urging parents to ensure that their children follow religion lessons at school.
He makes his appeal in a letter being read in churches today.
A few days ago, Education Minister Evarist Bartolo said that some 3,000 students in primary and secondary schools are currently exempt from religion lessons after requests made by their parents.
Mgr Scicluna said Catholic parents have a duty to choose religion as part of the education of their children.
Parents, he said, have a duty to ensure that children, from a young age, grow in the faith through example, deed and teaching.
Schools and the parish community did not replace the family, but complemented it, he said.