Louise Fletcher, who won the best actress Oscar for her indelible performance as Nurse Ratched in Milos Forman’s “One Flew Over the Cuckoo’s Nest,” died Friday at her home in France, according to a rep. She was 88.

The classic film, based on Ken Kesey’s novel and exploring the repressive tendency of authority through the story of the patients and staff of a psych ward, won five Oscars in 1976, including best picture and best actor for Jack Nicholson.

“One Flew Over the Cuckoo’s Nest” was the first film in more than four decades to sweep the major categories of best picture, director, actor, actress and screenplay. It was nominated for an additional four Oscars and was also a substantial box office hit.

In the American Film Institute TV special “AFI’s 100 Years… 100 Heroes & Villains,” Fletcher’s Nurse Ratched was named the fifth-greatest villain in film history — and second-greatest villainess, behind only the Wicked Witch of the West.

Ironically, the Ratched character had been softened in the script compared to Kesey’s original, and Fletcher gave a rather subtle performance, often conveying the character’s emotions simply through facial expressions, which is why she deserved her Oscar in the first place. Indeed, the actress even enables us to feel sorry for Ratched at more than one key moment in the film.

In a 2003 reappraisal of “Cuckoo’s Nest,” Roger Ebert declared that despite the Oscar, Fletcher’s performance “is not enough appreciated. This may be because her Nurse Ratched is so thoroughly contemptible, and because she embodies so completely the qualities we all (men and women) have been taught to fear in a certain kind of female authority figure — a woman who has subsumed sexuality and humanity into duty and righteousness.”

It could be argued, however, that the role of Nurse Ratched and the Oscar the actress earned for that performance ultimately did Fletcher more harm than good: In a review excoriating the horror film “Flowers in the Attic,” in which the actress starred in 1987, a frustrated and unsympathetic Washington Post writer opined, “Fletcher should talk to her agent about these stereotyped ‘evil’ roles, in which she has become increasingly tedious.”

But Fletcher may well have beseeched her agent for a greater variety of roles to no avail.

She had most recently appeared in the 2013 feature “A Perfect Man,” starring Liev…