Ten-year-old Alexander Kettler was playing in his grandmother's attic in her house near Hamburg, Germany, when he made the startling discovery.
He stumbled upon three wooden boxes of different sizes, one of which contained the mummy.
The other two contained a death mask and a canopic jar.
Alexander's father, Lutz Wolfgang Kettler, told several media that his late father had traveled to North Africa in the mid 1950s and the findings could be souvenirs he had brought home, possibly from Libya.
The mummy is currently being examined by forensic experts at Hamburg's Eppendorf University Hospital, to determine its age and origin.
The spokesman for the Verden district state prosecution, state prosecutor Lutz Gaebel, told Reuters there were "indications" the mummy could be 2,000 years old.