The Archdiocese of Trnava (Slovak: Trnavská arcidiecéza, Latin: Archidioecesis Tyrnaviensis) is a Latin Catholic archdiocese in western Slovakia including bigger part of the Trnava, and parts of Nitra and Trenčín regions.

In 2013 Pope Francis appointed Auxiliary Bishop Ján Orosch as the next Archbishop of the Archdiocese of Trnava.

The diocese was first created as Apostolic Administration of Trnava on 29 May 1922, subordinate to the Holy See, on the territory of Archdiocese of Esztergom which became part of the Czechoslovakia after 1918.

As of 2004, it covered an area of approximately 14,000 km² with a population of 1,930,000 people of which around 70% were of Catholic faith.

In January 2012, the Vatican had named the Czech bishop Jan Baxant as its apostolic visitor to the archdiocese of Trnava.