The teenager, identified as ASY, was found lying in a pool of blood near the apartment building in Al Butaina area in Sharjah on Friday, a police official said.
A police patrol and paramedics were called to the site where the boy was found.
"Our ambulances and rescue team rushed to the scene only to find the boy critical and bleeding," said the official.
The teenager was rushed to a nearby hospital but when his condition worsened he was moved to the Al Qasimi Hospital. He is currently admitted to the ICU and his condition is stated to be critical, the Gulf News reported, citing the police.
"It is believed that he attempted to commit suicide," the police said.
The building owners and tenants have been asked to exercise strict caution in all high-rise buildings here and ensure that all safety measures are in place.
An investigation into the matter have been launched, police said.