Scotland's animal welfare charity was alerted on Friday, July 25, after a resident of Greenwood Crescent in Coatbridge discovered the creature and took her home.
The female hermann's tortoise is now in the care of the charity's Lanarkshire Animal Rescue and Rehoming Centre in Hamilton, where she has been nicknamed Carrie.
Animal Rescue Officer Steph McCrossan said, "It's quite common for tortoises to go missing, especially during the summer when they are let out to enjoy some sunshine in the garden.
"They may have a reputation for being incredibly slow, but they are surprisingly fast and can quite easily dig their way under a fence or find a small gap in a hedge.
"Hopefully Carrie's owner will come forward so we can return her home as we think they may be very worried. If not, we'll find her a caring new owner."
Anyone who recognises Carrie is being urged to contact the Scottish SPCA's animal helpline on 03000 999 999.