The Diocese of Varaždin (Latin: Dioecesis Varasdinensis) is a Latin ecclesiastical territory or diocese of the Catholic Church in northern Croatia.

The diocese is centred in the city of Varaždin.

It is a new diocese, having only been erected on July 5, 1997, from the Archdiocese of Zagreb.

Bishop Marko Culej was the first to be head of the diocese.

[1] The Church of the Assumption of Mary into Heaven was built in 1646 and was proclaimed a cathedral on September 28, 1997.