The helicopter clipped some trees before the 8 p.m. crash, the Wakulla County Sheriff's Office said in a release.
The dead were identified as pilot Curtis Robert Clifford, 53, and passenger Bryan Ooten, 49, both of Tallahassee.
Sheri Noelle Devore, 45, of Tallahassee was injured and transported by medical helicopter to a Tallahassee hospital with unknown injuries.
"The three individuals were on their way back to Tallahassee after eating at a local restaurant. The helicopter clipped a tree limb and crashed and landed on its top. The tree limb took down a power line which hampered emergency worker efforts until the line could be turned off. The helicopter landed in a wooded and marshy area near the airport," the release said.
Federal Aviation Administration and National Transportation Safety Board investigators were on the scene.