This article contains titles of books in the Thoroughbred series, a children's novel series created by Joanna Campbell, as well as a spin-off series and other related books.

The spin-off series, Ashleigh, is 'supposedly' set in between Ashleigh's Hope and Ashleigh's Diary. However, this spin-off presents some major inconsistencies. In #2 Wonder's Promise (original series), Ashleigh states she's never attended a live horse race before; however, in the Ashleigh series (and Ashleigh's Diary, the Super Edition), she attends several races. This leads to the other error/inconsistency. In #7 Derby Day (Ashleigh series), it is said that Rhoda Kat is the first female jockey to win the Kentucky Derby. However, in the original series, Jilly Gordon clearly is. When the plague hits Ashleigh's family, various horses who survive or are sold before the first book, die (Midnight Wanderer, for example, who is put to sleep in the book, 'Goodbye Midnight Wanderer', apparently dies of the mysterious plague, rather than from the accident.) There is also large changes as to how Ashleigh and Mona get their horses. Ashleigh meets Stardust in Ashleigh's Hope and then owns (and must sell her) in Ashleigh's Diary, but in the Ashleigh Series she gets Stardust in #3 Waiting for Stardust and Stardust is expecting a foal in #15 Stardust's Foal (which this in never mentioned in Ashleigh's Hope or Ashleigh's Diary). In Ashleigh's Hope Mona gets a Thoroughbred she names Frisky on Thanksgiving Day, rubs it in, won't let Ashleigh ride Frisky, and the girls have a big fight. But in the Ashleigh Series Mona gets a Thoroughbred for Christmas, names her Frisky like she and Ashleigh had planned, says she is sorry and is not trying to rub it in as soon as she tells Ashleigh, and asks her to come over tomorrow to ride Frisky. The entire Ashleigh series is in a sort of "time bubble" and none of the events really line up with the events in the other Thoroughbred books, so it is almost a stand alone series in and of itself.

1. Lightning's Last Hope
2. A Horse For Christmas
3. Waiting For Stardust
4. Good-Bye Midnight Wanderer
5. The Forbidden Stallion
6. A Dangerous Ride
7. Derby Day
8. The Lost Foal
9. Holiday Homecoming
10. Derby Dreams
11. Ashleigh's Promise
12. Winter Race Camp
13. The Prize
14. Ashleigh's Western Challenge
15. Stardust's Foal

Ashleigh's Thoroughbred Collection contains three stand alone books that do not tie into/effect the storylines of the other series. Battlecry Forever! is a slight exception though. It is about Battlecry (the sire of Fleet Goddess, a filly that Ashleigh Griffen purchases in #5 Ashleigh's Dream of the Thoroughbred series) but it is considered stand alone (due to not playing a major role in the storyline of Thoroughbred), even though it is also still technically considered the only book written outside of the Thoroughbred series that is canon.

• Battlecry, Forever!
• Star of Shadowbrook Farm
• The Forgotten Filly