US archaeologists on Friday said they discovered the tomb by accident while working on a nearby site.
Still unknown is whose mummies are in the five wooden sarcophagi with painted funeral masks, surrounded by alabaster jars inside the undecorated single-chamber tomb.
The tomb, believed to be some 3000 years old, dating to the 18th Dynasty, does not appear to be that of a pharaoh, said Edwin Brock, co-director of the University of Memphis that discovered the site.
No royal tomb
Brock said: "I don't think it's a royal tomb, maybe members of the court. Contemporaries of Tutankhamun are possible - or of Amunhotep III or even Horemheb."
Zahi Hawass, Egypt's antiquities chief, said: "Maybe they are mummies of kings or queens or nobles, we don't know. But it's definitely someone connected to the royal family."
"It could be the gardener," Schaden joked to Hawass at the site. "But it's somebody who had the favour of the king because not everybody could come and make their tomb in the Valley of the Kings."
So far, archaeologists have not entered the tomb, having only opened part of its 1.5-metre-high entrance door last week. But they have peered inside the single chamber to see the sarcophagi, believed to contain mummies, surrounded by around 20 pharaonic jars.