Two hand-painted concrete Minis were stolen from a grave at the new cemetery in Wellingborough Road, Irthlingborough.
The theft took place sometime between 6am on Tuesday, October 10, and 8.30am on Saturday, October 14.
A police spokesman said: “One of the Minis is very heavy, painted orange, approximately 45cm by 30cm with artificial flowers planted in the middle.
“The other Mini is red, approximately 29cm by 21cm also with artificial flowers planted in the middle.
“They are both of high sentimental value to the owner.”
Witnesses or anyone with information about the stolen ornaments can contact Northamptonshire Police on 101 or Crimestoppers anonymously on 0800 555111.