An 11-year-old boy endured a terrifying, 20-minute trip Sunday with a car thief who’d just boosted his dad’s SUV in East Harlem — before he was dumped in the Bronx more than five miles away, cops said.

The boy was sitting in the front passenger seat of his dad’s 2017 Nissan Rogue, which was left running on Third Avenue near East 121st Street around 8 p.m., cops and police sources said.

The 36-year-old dad had just popped into a shop nearby.

But a short time later, the suspect climbed into the driver’s seat — peeling off with the boy still inside, cops and sources said.

“I’m a friend of your dad’s,” the suspect allegedly told the boy. “Don’t worry.” 

As the thief drove off, he lost control, causing damage both to his stolen ride and an unoccupied car parked nearby, cops said. 

About 20 minutes later, the suspect stopped the SUV at Lafayette and Bolton avenues in the Castle Hill section of the Bronx — more than five miles away — and let the boy out, unharmed, cops said. 

The kid used his phone to call his dad, who then notified the police, cops said. 

Officers from the 43rd Precinct reunited him with his dad, authorities said. 

The stolen SUV was found five hours later in the confines of the 108th Precinct, which covers southwest Queens, according to authorities. 

The suspect was still on the loose Monday. 

He appears to be in his mid-30s and was wearing a black cargo jacket with a red hoodie, police sources said.