Yes, you do need tickets to access certain parts of the Milan Cathedral complex.

1. Main Cathedral Area: The main area of the cathedral often requires a ticket for entry, especially during peak tourist seasons. This ticket grants you access to explore the grandeur of the interiors, including the vast nave, the chapels, and the stunning stained-glass windows.
2. Rooftop Terraces: One of the highlights of the Duomo is its rooftop terraces, which provide panoramic views of Milan and a close look at the cathedral’s spires and sculptures. Accessing the terraces requires a separate ticket. You can choose to climb the stairs or take the elevator, though the latter might come with an additional fee.
3. Archaeological Area: Below the cathedral, there’s an archaeological area showcasing remnants of ancient baptisteries and churches. A ticket is needed to delve into this historical treasure trove.
4. Duomo Museum and Church of San Gottardo: Close to the main cathedral, the museum and the church often come as a combined ticket or a part of a comprehensive Duomo pass. Here, you can explore artifacts, sculptures, and artworks related to the cathedral’s history.
5. Special Guided Tours: For a more in-depth experience, you can opt for guided tours, which not only require a ticket but also offer enriching insights into the cathedral’s history, architecture, and artworks.