There are over 100 Magic Tree House books when you include all the connected series, not just the original numbered adventures.

How many Magic Tree House books are there?

For the full “Magic Tree House universe”:

  • About 66 fiction books (main Magic Tree House + Merlin Missions).
  • About 44 non‑fiction Fact Tracker companion books.

That makes around 110 books total in the extended series (and the author continues to add more from time to time).

If you only mean the original, early chapter-book adventures with Jack and Annie (the core “Magic Tree House” line), there are roughly 38–40 main- series titles , depending on how you count later renumbered Merlin Missions and special editions.

Quick breakdown

  • Main Magic Tree House series : about 38 books so far.
  • Merlin Missions (longer, for slightly older kids): 27 books.
  • Fact Trackers / Research Guides : 44 non‑fiction companions.

So if you’re asking “how many Magic Tree House books are there altogether?” the best current answer is: about 110 books in total, and still growing.

Information gathered from public forums or data available on the internet and portrayed here.