The two 17-year-olds, who have not yet been named, were found by police at Huntcliff in Saltburn at about 19:00 GMT on Friday.
Cleveland Police said: "Inquiries are ongoing to establish the circumstances of exactly what happened."
The families of the boys are being supported by specialist officers, police added.
The coastguard also attended the scene to assist police.
Any witnesses who were in the area of Huntcliff around the time of the incident are asked to contact Det Sgt Paul Hodgson at the force on the non-emergency number 101.
The bodies of two teenage boys have been found at the bottom of a cliff, police have said.