Building upon the acclaim Pygmalion had received from German-language production and publication, the original English production of the play at His Majesty's Theatre was likewise a success, securing Shaw's reputation as a popular playwright. Still, contemporary reviews of Pygmalion are mixed, revealing the somewhat prejudicial views English critics continue to hold towards Shaw's work. For example, an unsigned review in the Westminster Gazette, reprinted in Shaw: The Critical Heritage, criticized many aspects of the production but had qualified praise for the play, "a puzzling work." Aware that Shaw usually "does not use the drama merely as a vehicle for telling stories," the critic expressed a curiosity about what "the foundation idea" of Pygmalion might be. "Curiosity, in the present instance," however, "remains unsatisfied. There are plenty of ideas, but none is predominant.''

Alex M. Thompson, meanwhile, wrote in a review in the Clarion that "Britain's most famous playwright has won his place at last on the stage of Britain's most famous playhouse" but regretted that "while the great playwnght's really significant plays" were wasted through production elsewhere, "the play admitted to our classic shrine is one whose purpose, according to the author himself, is 'to boil the pot.'" H. W. Massingham, in a review for the Nation, declared that "there is a fault in the piece as well as in its production," namely that Shaw "observes too coldly'': in pursuing the clash of wits, the excitement of argument, he obscures real beauty and affection. Shaw, somewhat like Higgins, "hides his spirituality or his tenderness under a mask of coarseness," to the extent that he "has failed to show his audience precisely what he meant."

The sensation caused by Shaw's use of the mild profanity "bloody" (breaking with tradition at His Majesty's Theatre) went a long way to ensure the publicity for Pygmalion, but many critics found the language of the play shocking. T. F. Evans commented in his notes for Shaw: The Critical Heritage, that "[it] is almost impossible ... to assess accurately the critical response to the play itself because of the totally disproportionate amount of space, time and attention that was given to the use by Shaw... of the word 'bloody'.... Some critics who might have been expected to give largely favourable comments on the play seem to have allowed the use of the adjective to affect them. "By 1938, however, the year Pygmalion was made into a movie, Shaw's text was still dramatic and challenging but much of the shock had faded. Of the film version, Desmond MacCarthy observed in Shaw: The Plays that "'bloody' still gets its laugh, but it no longer releases the roar that greets the crash of a taboo."

In his 1929 study A Guide to Bernard Shaw, Edward Wagenknecht demonstrated the delicate balance many critical interpretations of Shaw in that era tried to maintain, explaining how Shaw had succeeded despite breaking many established conventions of dramatic art. Shaw "revolted" against deeply-held ideas that literature is writing which supersedes a specific purpose other than to communicate life experience, and is not didactic. "It is amazing,'' Wagenknecht wrote, "that a man whose theory of art is so patently wrong should have achieved such a place as Shaw has won."

By the end of Shaw's life, his status as perhaps the greatest single English dramatist since Shakespeare was secure, but nevertheless critical opinion on him appeared mixed and in many cases prejudiced. Eric Bentley wrote in his book Bernard Shaw, 1856-1950, that in reviewing the already voluminous writing on Shaw, "I found praise, but most of it naive or invidious. I found blame, but most of it incoherent and scurrilous.'' Perhaps Shaw's complexity of thought provoked these mixed (and largely unsatisfying) critical assessments, to the extent that to some critics "Shaw, the champion of will and feeling, is an arch-irrationalist," but to others "Shaw, the champion and incarnation of intellect, is the arch-rationalist." In Pygmalion Bentley found a play of "singularly elegant structure ... a good play by perfectly orthodox standards" needing "no theory to defend it."

In his summary of the play's merits, Bentley avoided the tendency of earlier critics to distinguish sharply between various aspects of Shaw's work, instead celebrating the intimate connection between them. Pygmalion, he wrote, "is Shavian, not in being made up of political or philosophic discussions, but in being based on the standard conflict of vitality and system, in working out this conflict through an inversion of romance, in bringing matters to a head in a battle of wills and words, in having an inner psychological action in counter-point to the outer romantic action ... in delighting and surprising us with a constant flow of verbal music and more than verbal wit." Bentley' s modern assessment of the complexity of Shaw's political thought and dramatic method established a precedent for much Shavian criticism of the last fifty years.

Beginning immediately with the first English production of Pygmalion, a popular debate developed as to whether there should have been a romantic ending between Higgins and Liza. Shaw insisted that such an ending would have been misery for his characters but producers and audiences nevertheless tended to prefer a romantic ending. MacCarthy expressed the sentiments of many when he wrote about the original production: "when the curtain fell on the mutual explanations of this pair [Higgins and Liza], I was in a fever to see it rise on Acts VI and VII; I wanted to see those two living together."

When the play was first published in 1916, Shaw added an afterword which recounted what Liza did after leaving Higgins and was intended to show to audiences that there was to be "no sentimental nonsense'' about the possibility of Higgins and Liza being lovers. The English-language film of Pygmalion gave Shaw another opportunity to remove "virtually every suggestion of Higgins's possible romantic interest in Liza." He was to discover, however, at a press show two days before the film's premiere, that the director had hired other screenwriters who added a "sugar-sweet ending" in which Higgins and Liza are united as lovers. MacCarthy commented in 1938 that the effect of the changes in the film version "is merely that of a wish fulfillment love story of a poor girl who became a lady and married the man who made her one." He observes that the difference is "due to a peculiarity inherent in the art of cinema itself (a need for closure), and that the changed ending is no doubt what accounts for the film's "immense popularity."