When No Exit was first produced in Paris in 1944, the critical response was mixed, due in part to the political climate of the time. Much of France was occupied by Germany. Sartre was identified with the Resistance, the French underground movement that sought to overthrow the German occupation. No Exit was regarded by many as subversive, full of in-jokes and subtle wartime criticism. Critics might have been afraid to openly praise such a play for fear of repercussions, though No Exit was produced by permission of German censors. Those critics who favored the Germans or collaborated with them would not have wanted to praise something this controversial. Several critics, including André Castelot, called for censoring the play.

Numerous French critics, regardless of their political views, agreed that the core idea of the play was brilliant. But there was controversy among critics and audiences alike over the brutality of the crimes committed by the characters as well as the character of Inez herself. Openly lesbian characters were unusual at the time.

No Exit was first produced in the United States on Broadway in December, 1946. American critics and audiences shared some of the French concerns over the characters, but many did not know what to make of the play as a whole. Wolcott Gibb, writing in The New Yorker, attributed the play's success in Europe (the play was also a hit in London) to the Europeans' "temperament." Gibb dismissed No Exit as "little more than a one-act drama of unusual monotony and often quite remarkable foolishness.'' The critic for Newsweek was not as negative, calling the play ‘‘weird and fascinating.’’ Like their European counterparts, many American critics were intrigued by Sartre's concept of hell, but many Americans thought the play became repetitious near the end. Joseph Wood Krutch of The Nation took this view. He wrote, "Chief among the virtues is a genuinely macabre quality which makes itself felt most effectively during the first fifteen minutes. Unfortunately, like most plays based upon a conception which can be effectively stated in a few words, No Exit suffers from the fact that the interest tends to decline steadily from the moment the conception has been grasped.’’

One point that the American critics of the time debated was the nature of existentialism, since No Exit was regarded as an existentialist play. The philosophy was relatively new and not completely understood in the United States. Since its original productions, existentialism has become widely studied and discussed by scholars. The play has been debated in these terms. No Exit and its themes are now better understood, and the play is generally regarded as a classic. Unlike most of Sartre's other plays, No Exit has retained an accessibility because it is not rooted in a specific time and place.

There has been an extensive critical debate over the meaning of the play's most famous line, "Hell is other people." Many believe it means that interpersonal relationships are inevitably hellish. Others, including Sartre, disagree, arguing that it means people are too dependent on other people's opinions of them. Critics and scholars also have debated the meaning and nature of Sartre's hell, comparing it to other literary depictions. In an essay Jacques Guicharnaud contributed to Sartre: A Collection of Critical Essays, he wrote, "the play is not a metaphor of Hell but that the image of Hell is a metaphor of the hopeless suffering of individuals in search of their definitions in the eyes of others, yet constantly brought back to themselves.’’