The child - who is just nine years old - has received a lawsuit from a man demanding he goes to court over the debt of 561,000 rubles (about £12,000).
The money was apparently loaned to the boy's mother by the man before her death.
When she died leaving all her assets to her son, he then also became liable for her debts.
His official guardian is to represent the child in court, in a case which a spokeswoman said was not illegal.
Speaking from Moscow's Tverskoi Court, the spokeswoman confirmed that the court received a lawsuit from a man named Panikorovsky and that he was seeking to collect the money from the little boy. She said: "There is nothing illegal in such a lawsuit."
What an awful thing for a child to have to go through after losing his mother!