- The Serpent Pool (2005)
- The Amber Rose (2006)
- The Gypsy Angel (2007)
- The Secret Pearl (2009)
- The Silver Swan (2010)
- The Golden Lily (2011)
- The Crimson Petal (2013)
- The Midnight Hour (2014)
- The Shadow Queen (2015)
- The Witch's Daughter (2016)
- The Betrayal of the Crown (2017)
- The Lost Princess (2019)
- The Forbidden Rose (2020)
- The Last Empress (2021)
In addition to historical novels, Gainsborough has also written historical biographies and non-fiction books.
Her works include "Elizabeth: The Queen's Life" (2007), "The Tudors: A History of England's Most Notorious Dynasty" (2009), "The Plantagenets: A History of England's Most Powerful Dynasty" (2011), and "The Royal House of Windsor: A History of the British Monarchy" (2013).