According to officials, the plane struck a house in the area of Golden Hill Avenue just before 6:00 p.m.
Danbury Mayor Mark Boughton said the aircraft made a direct hit into the roof.
He added that the operator was OK, but is being transported to a local hospital for observation.
There were three people in the house at the time, police said, and they were transported to the hospital for evaluation as well.
Danbury police said the 2016 Alisport Silent 2 Electro glider plane lost power and conducted an emergency landing. The glider plane took off from Danbury Municipal Airport, police said.
The Airport Administration, FAA, and National Transportation Safety Board are working the investigation.
Free download: Access Connecticut breaking news, weather, stream newscasts live and more on-the-go with News 8 alerts directly to your phone.