Gray Lady Down is a 1978 American submarine disaster film directed by David Greene and starring Charlton Heston, David Carradine, Stacy Keach, Ned Beatty, Ronny Cox and Rosemary Forsyth, and includes the feature film debut of Michael O'Keefe and Christopher Reeve.

Surfaced and returning to port, the submarine, USS Neptune, is struck by a Norwegian freighter en route to New York in heavy fog.

As technical malfunctions increase, the submarine's sections get flooded and men die, crewmen have nervous breakdowns and tensions grow between the commanding officers.

The film ends with a somber Blanchard climbing out of the DSRV and being welcomed aboard the rescue ship USS Pigeon by Bennett and his officers.

Vincent Canby, reviewing for The New York Times, wrote "It's been composed with its crises so evenly spaced that you ache for a station break bracketed by commercials...