In the swimming pool scene with the mother near the end, the actress didn't know it, but those weren't fake skeletons.

The scene where the ghosts stacked the chairs on the kitchen table was filmed in one take with no cuts. As the camera followed Diane Freeling to the kitchen sink, the crew members rushed to the table, put an already built pyramid of chairs on the table and then took away the individual chairs.

After the first Poltergeist movie was made, actress Dominique Dunne (Dana Freeling) was murdered by her estranged boyfriend in 1982. Actor Julian Beck (Kane) died of stomach cancer in 1985 after filming the second film. And after the third, actress Heather O'Rourke (Carol-Anne) died in 1988 from cardiopulmonary arrest brought by intestinal stenosis. This has (annoyingly) been called "The Poltergeist Curse."

It is a little-known fact that it was actually Steven Spielberg's hands that tore the flesh off the investigator's face in the bathroom.