Emergency crews were called to Wain Wath, near Keld in Swaledale at about 17:10 BST on Friday
They had received reports of four people who had been swimming and got into difficulties.
The teenager was pronounced dead by police and two others were taken to James Cook University Hospital by air ambulance.
Wain Wath on the River Swale in the Yorkshire Dales national park is a popular spot for paddling and swimming.
A 19-year-old man from Middlesbrough has died while swimming at a waterfall in North Yorkshire.