The year-old collie cross was found dead in Glasgow weighing about one-third of what it should have been.
The SSPCA said the case was "one of the worst" it had ever investigated.
The dog's body was found behind a block of flats in Southdeen Avenue in Drumchapel on Tuesday.
It weighed just 7kg. The normal weight for the breed is 20kg.
The dog also had overgrown claws, indicating that it had not been outside for a long time.
Senior inspector Billy Linton said: "This is one of the worst cases of starvation we have ever been involved in.
"The vet who examined the body was very shocked and had never seen anything like it."
The SSPCA have asked anyone with any information to contact them on 03000 999 999.