"It is something, in color, called The Terror, which it most certainly is."
Bosley Crowther, The New York Times

"Secret crime and sorcery in a mystery castle is the basis for this rather slow and old-fashioned type of creepy macabre tale with a supernatural element; but as a blood-curdler its horrors are on the mild side and suspense and excitement are limited, though sufficient to make it acceptable to horror film fans."
CEA Film Report

"Good film? Frankly, no! In fact, to make a well-deserved pun it's frequently terrible!...the playing's downright ludicrous. The worst offender being Jack Nicholson, performing with a degree of woodenness unmatched this side of Epping Forest."
Films and Filming

"Corman establishes himself as a highly creative producer-director with this excellent film. Much atmosphere chills & mood in tale of a drafty castle, witchcraft, haunted woods, tombs, and corpses that aren't really dead. Ingmar Bergman-like in many ways, this is one of the least heralded, most important films in many years."
Castle of Frankenstein

"All the traditional ingredients are included, the rambling castle with secret passages, almost continuous thunderstorms and ghostly appearances and disappearances, but too much footage is spent on suspense that hangs only on time, and the whole is not helped by a stilted script and a hero who registers emotion in a nasal monotone. Boris Karloff as the Baron is of course always worth seeing."
Kinematograph Weekly

"The whole thing is directed by Roger Corman, who is highly thought of in horror circles, but whose other recent effort, The Masque of the Red Death [1964], struck me as being nearly as metaphysically obscure as this one. He does have a nice eye for scenery and colour photography, though. Some of the shots in this one have a Bergmanesque quality of imagination."
Western Daily Press

"The Raven was polished off with three days to spare. Instead of giving his star, the venerable Boris Karloff, a breather, Corman had a script whipped up overnight, and while two assistants shot backgrounds in the Big Sur, he propped his aged trouper against those Raven sets still standing and called the hastily-pasted end-product The Terror."
Denis Gifford, A Pictorial History of Horror Movies

"This complicated plot is hard to follow and even harder to believe..."
Peter Underwood, Boris Karloff and his Films

"Hodge-podge of horror with a dozen illogical plot twists fused into one Pathecolor puzzle. Boris Karloff loves his wife, who is dead, yet lives in his timeless castle of rotting bodies and the like...C'est la vie."
Ed Naha, Horrors: From Screen to Scream

"There's some notable incoherency and a smooth, rambling confusion in the film that, nevertheless, does little to detract from its amazing visual quality and mysterious fascination. It's all Karloff's vehicle from start to finish."
Calvin Beck, Heroes of the Horrors

"Roger Corman is famous for turnin' 'em out fast. This one was supposedly done in three days...Of course it's disjointed, but think of it as an exercise in economy and speed. A legendary mess."
Michael Weldon, The Psychotronic Encyclopedia of Film

"A patchwork quilt shot by Corman in just a few short days using sets left over from his more accomplished Raven...An incomprehensible mess."
John McCarty, Video Screams

"...a confusing but enjoyable horror thriller..."
Paul M. Jensen, Boris Karloff and His Films

"There are many passages of Nicholson exploring the dark castle-obviously, this is filler. There are no scares and nothing really happens until the end of the film. It's pretty boring; enjoyable only for watching Karloff (who's good) and Nicholson (who's pretty lousy) wing it, and for ridiculous plot twists which were probably inserted just to confuse us."
Danny Peary, Guide for the Film Fanatic

"An honorary member of the Poe cycle by virtue of its necrophiliac theme, the film is likeable but indifferently acted (Karloff excepted) and lacking in any sort of compulsion."
The Aurum Encyclopedia of Film: Horror

"For such a hurried whim with so many cooks in the broth, The Terror is a surprisingly good film. Although it is an original work, it uses many of the tropes that Corman set up with his Edgar Allan Poe films - the tortured mood; people haunted by the crippling weight of past events; mysterious castles and their doom-laden residents; the innocent traveler who stumbles by; mystery women... Corman sustains the mood particularly well here."
Richard Scheib, The SF, Horror and Fantasy Film Review

"This is one of Corman's ingenious afterthoughts... Unfortunately, the burden of the film falls on the neophyte shoulders of young Jack Nicholson... Scenes fluctuate between campiness and Gothic splendor, which is no surprise, considering how the film was made."
Gene Wright, Horrorshows

"(Nicholson's) brash, uninflected performance is completely at odds with Boris Karloff's understated menace. Ultimately, The Terror's only relationship to Poe is that it featured the same stars and the sets used in The Raven."
Alain Silver and James Ursini, More Things Than Are Dreamt of

"Needless to say, the result is often uneven. Given the quality of the people involved, this could have been a much better film, but surprisingly, it really isn't that bad."
Welch Everman, Cult Horror Films

"Engaging chiller nonsense with Karloff the mysterious owner of a castle where eerie deeds occur."
Leonard Maltin Movie Guide

"Another surprisingly enjoyable prowl through a creepy Corman castle whose incidental pleasures, notably Karloff's commanding performance, compensate for the (largely) incomprehensible narrative."
Alan Frank, The Films of Roger Corman

"With scenes directed by Jack Hill, Francis Coppola, Monte Hellman and others, this is a curiously poetical, if sometimes incoherent hodgepodge, but a worthwhile diversion if seen in a clean print..."
Tim Lucas, Video Watchdog

"While The Terror, in its finished form, made almost no sense at all (not surprising, since it barely had a plot) and Nicholson showed little sign of the actor he has gone on to become, it proved to become another box-office wonder."
Gordon B. Shriver, Boris Karloff: The Man Remembered

"For the record, the plot does so make sense."
Clayton Trapp, Brilliant Observations on 1173 Films

"A lot of separate components pasted together with Band-Aids."
Jack Nicholson, interviewed by Bill Davidson, The New York Times

Compiled by Richard Harland Smith