How to Read the Gallagher Girls Series in Order
Welcome to Gallagher Academy for Exceptional Young Women, a highly selective boarding school where the classes cover advanced chemical warfare, codebreaking, fourteen languages, and, of course, covert operations. Ally Carter's bestselling Gallagher Girls series has captivated young adult readers since 2006 with its irresistible combination of high-stakes espionage, deep female friendships, and lighthearted high school romance.
If you are planning to join Cammie Morgan and her squad of genius teen spies, you have a couple of reading orders to choose from. While the core series consists of six main novels, several crucial novellas, crossover stories, and short epilogues enrich the narrative. Below, we break down the recommended reading order, detail the publication timeline, and explain where the side stories fit to give you the best possible reading experience.
The Recommended Reading Order: Publication Order
While a prequel novella exists, we strongly recommend reading the Gallagher Girls series in publication order. Starting with the first novel published in 2006 allows you to experience the mysteries of the Gallagher Academy and the development of the characters exactly as the author intended. The prequel novella, published years after the main series ended, contains nods and context that are much more satisfying to read once you are already familiar with the characters.
- I'd Tell You I Love You, But Then I'd Have to Kill You (Book 1) – Published in 2006. This is the ideal entry point, introducing Cammie Morgan, her brilliant roommates (Bex, Liz, and Macey), and the double life they lead.
- Cross My Heart and Hope to Spy (Book 2) – Published in 2007. The stakes rise as the girls face a security breach and discover the existence of a rival boys' spy school, Blackthorne Academy.
- Don't Judge a Girl by Her Cover (Book 3) – Published in 2009. A political campaign, an attempted kidnapping, and family secrets push the girls into real-world danger.
- Only the Good Spy Young (Book 4) – Published in 2010. Cammie finds herself targeted by a rogue organization, leading to a hunt for a double agent within the school's own walls.
- Classified Material (Book 4.5) – Originally serialized online, this collection of bonus scenes and diary entries bridges the emotional and plot gap between the fourth and fifth books.
- Out of Sight, Out of Time (Book 5) – Published in 2012. Cammie wakes up in the Alps with no memory of the last several months, kicking off a race to reconstruct her lost summer.
- Double Crossed: A Spies and Thieves Story (Book 5.5) – Published in 2013. A crossover novella featuring Macey McHenry and Kat Bishop from Carter's companion series, Heist Society.
- United We Spy (Book 6) – Published in 2013. The grand, action-packed finale where Cammie and her friends take on the Circle of Cavan to save the world.
- A Gallagher Wedding (Book 6.5) – A short epilogue story tracking the future of the characters, originally included in special editions of the final book.
- The Spies That Bind (Prequel Novella / Book 0.5) – Published in 2018. A prequel focusing on Cammie's first days at the academy and how she met her core group of friends.
The Chronological Reading Order
If you are revisiting the series or prefer to follow Cammie's timeline from the absolute beginning, the chronological order places the 2018 prequel first. This arrangement allows you to see how the core friendships form before the main action kicks off in the freshman and sophomore years of high school.
- The Spies That Bind (Book 0.5)
- I'd Tell You I Love You, But Then I'd Have to Kill You (Book 1)
- Cross My Heart and Hope to Spy (Book 2)
- Don't Judge a Girl by Her Cover (Book 3)
- Only the Good Spy Young (Book 4)
- Classified Material (Book 4.5)
- Out of Sight, Out of Time (Book 5)
- Double Crossed: A Spies and Thieves Story (Book 5.5)
- United We Spy (Book 6)
- A Gallagher Wedding (Book 6.5)
What to Know Before You Start
Before diving into Cammie's covert world, there are a few important details to keep in mind regarding tone, spin-offs, and continuity:
1. Can the books be read as standalones?
No. The series features an overarching mystery and continuous character arcs. While the first two books have self-contained school-year plots, starting with Book 3 (Don't Judge a Girl by Her Cover), the series shifts into a continuous, high-stakes thriller format that culminates directly in the final book. Reading them out of order will lead to major spoilers and confusion.
2. The Heist Society Crossover Connection
Ally Carter's other major young adult franchise is the Heist Society series, which follows Kat Bishop, a young master thief. The two series share a universe. This connection is made explicit in the crossover novella Double Crossed: A Spies and Thieves Story. In this story, Macey McHenry (a Gallagher Girl) and W.W. Hale V (a Heist Society character) meet at a high-society gala. While you do not need to read the Heist Society books to understand Gallagher Girls, doing so adds a layer of fun to the crossover.
3. The Prequel Novella Placement
The Spies That Bind was published in 2018, five years after the publication of the final main book. Because it was written with hindsight, it features character dynamics that are more enjoyable if you already love the cast. If you are a first-time reader, save it for the end as a nostalgic trip back to the beginning.
Summary of the Gallagher Girls Universe
Spanning six main novels and multiple companion works published between 2006 and 2018, Ally Carter's Gallagher Girls remains a cornerstone of 2000s and 2010s YA fiction. Its enduring legacy is its celebration of female intelligence, agency, and sisterhood. The bonds between Cammie, Bex, Liz, and Macey are the true heart of the series, showing readers that while romance and spycraft are exciting, loyal friendships are the ultimate superpower.