The School for Scandal has been widely admired. The English critic William Hazlitt was particularly effusive in his praise of Sheridan's comedies in general ("everything in them tells; there is no labour in vain") and of this play in particular:
The 'School for Scandal' is, if not the most original, perhaps the most finished and faultless comedy which we have. When it is acted, you hear people all around you exclaiming, "Surely it is impossible for anything to be cleverer." The scene in which Charles sells all the old family pictures but his uncle's, who is the purchaser in disguise, and that of the discovery of Lady Teazle when the screen falls, are among the happiest and most highly wrought that comedy, in its wide and brilliant range, can boast. Besides the wit and ingenuity of this play, there is a genial spirit of frankness and generosity about it, that relieves the heart as well as clears the lungs. It professes a faith in the natural goodness as well as habitual depravity of human nature.
Edmund Gosse called the play "perhaps the best existing English comedy of intrigue", while Charles Lamb wrote that "This comedy grew out of Congreve and Wycherley", but criticised "sentimental incompatibilities" even while admitting that "the gaiety upon the whole is buoyant."
Samuel Barber composed his first full orchestral work as an overture programmed for the play.
On the other hand, the play has also in modern times been criticised for some hints of anti-Semitism, specifically "the disparaging remarks made about moneylenders, who were often Jewish." It is true that the moneylender Moses is portrayed in a comparatively positive light, but the way he is described (as a "friendly Jew" and an "honest Israelite" by Rowley in III.1) suggest that he is in some way to be considered an exception to Jews in general; also, his own usurious business practices as stated to Sir Peter are clearly less than exemplary (e.g., his statement "If he appears not very anxious for the supply, you should require only forty or fifty per cent; but if you find him in great distress, and want the moneys very bad, you may ask double" [III.1]). It may be significant that in Johann Zoffany's portrait of Robert Baddeley as Moses, we find that "Under his arm Moses holds a rolled parchment of the Surface family tree that is used as an auction hammer, and he seems to be ticking off pictures in the catalogue", although in the play Careless is the auctioneer in the relevant scene (IV.1) and Moses has a relatively minor role.
It is notable that at least one modern production (Los Angeles, 2004) has "sanitized most of what could be deemed as anti-Semitic content" by changing references to "Jews" and "Jewry" to "moneylenders"—a practice that a reviewer termed "PC-ification" of the play. Another production, by the Seattle Shakespeare Company in 2007, reportedly did not tamper with this aspect of the text and was commended by a reviewer for "the courage to face the script's unsavory side."
Another criticism that has been made of the play involves the characterisation. A writer in the 19th century periodical Appleton's Journal states that
The great defect of 'The School for Scandal' — the one thing which shows the difference between a comic writer of the type of Sheridan and a great dramatist like Shakespeare – is the unvarying wit of the characters. And not only are the characters all witty, but they all talk alike. Their wit is Sheridan's wit, which is very good wit indeed; but it is Sheridan's own, and not Sir Peter Teazle's, or Backbite's, or Careless's, or Lady Sneerwell's.
The style of the play has also made it at times a problematic work to make effective in today's theatre. In appraising a 1999 staging of Sheridan's comedy at the Guthrie Theater in Minneapolis, Minnesota, one critic found the "staunchly orthodox production" to be lacking, commenting that
Sheridan's satirical bite, which is as venomous as Molière's and as quick as Wilde's, comes not from epigrammatic flourishes, but from the subtle undermining of Georgian social mores... In this realm, gossip is a form of social control, wielded by the essentially impotent elite to force conformity among their peers...
Another reviewer in Variety noted of a 1995 production starring Tony Randall as Sir Peter Teazle that Sheridan's play was "such a superbly crafted laugh machine, and so timeless in delivering delectable comeuppance to a viper's nest of idle-rich gossipmongers, that you'd practically have to club it to death to stifle its amazing pleasures" – before claiming that this is precisely what the production being reviewed had done.
But in the hands of a talented director and cast, the play still offers considerable pleasure. A New York production of 2001 prompted praise in the New York Times for being "just the classy antidote one needs in a celebrity-crazed world where the invasion of privacy is out of control, but the art of gossip is nonexistent."