Incorrectly regarded as goofs: Early on, Jeff wheels himself over to the window and bumps his leg (the one in the cast) against the wall below the window, yet he doesn't grimace at all. Once a broken leg in a cast begins healing, it's no more sensitive to such bumps than an uninjured leg.
Continuity: When Lisa places her slippers into her overnight case (while sitting on Jeff's lap), they are tossed in, more to the side of the case. Later, when the detective views the suitcase, the slippers are neatly placed and sitting upright.
Continuity: When Jeff is getting back into the wheelchair after Stella has given him a massage, his pajama top jumps from being unbuttoned to buttoned between shots.
Continuity: When Jeff grabs the box of flashbulbs, all four can be seen in the box. But when he backs up more, there are only two left.
Miscellaneous: After Lisa sees Thorwald tie up the trunk, and the camera dollies forward to a close up, there are creaks from the floorboards and footsteps heard from the camera crew.
Continuity: Lisa takes the binoculars away from Jeff and wraps the neck cord around them before putting them on a small cupboard. When Jeff picks up the binoculars later, the neck cord is no longer wrapped around them.
Continuity: The amount of Brandy in the detective's glass increases between shots.
Continuity: When Lisa goes to Jeff's house to celebrate his last week with his cast, she places two candles onto the table next to him, the candles are not lit. A little later in the same scene, Lisa walks into the kitchen, and when she returns, the candles are lit.
Continuity: The location and angle of the shadows of the "sun" are in the same place at in the morning and at night.
Continuity: At the end of Jeff's first massage, Stella places the bottle with the green liquid on the side table without replacing the cap. As Stella is packing to leave, the bottle is capped as she places it in her bag.
Audio/visual unsynchronized: While Lisa and Stella are digging up the flowers (about 92 minute mark) the pianist is shown playing with other musicians. When the harmonica players starts to play, a saxophone is heard although none is visible. The harmonica is subsequently heard also.
Audio/visual unsynchronized: At 00.52.52: When Jefferies' nurse goes to the door saying she's going to find out the name of the freight carrier that is taking off with the trunk, someone who sounds nothing like Jimmy Stewart has dubbed him with the peculiar sounding line "I'll keep an eye on the alley". Jimmy Stewart is holding the binoculars over his mouth but we can see that he's not moving his lips! Prior to that, when he says "don't do anything foolish" his lips are still moving after the audio is heard.
Continuity: When Thorwald returns home from one of his trips out in the rain lugging his suitcase, the camera (from Jeff's point of view) pans from a glimpse of Thorwald in the street, across Miss Torso's apartment where she is preparing to go to bed, to the second floor hallway where Thorwald is walking toward his apartment. This observed action takes only a few seconds - an impossibly short time frame for Thorwald to have entered his building through its front door, walked over to the stairwell, climbed the stairs to the second floor and then be seen walking along the second floor hallway.
Factual errors: The image retention effect depicted in Jeff's apartment, when he fires the flashbulbs to temporarily blind Thorwald, is based upon the color of the light source. The type of flashbulbs used were a Clear type, appearing bluish to the eye, not red as the POV shots indicate.
Continuity: When Jeff is watching Miss Lonleyhearts, and drinks a silent toast to her, he has drunk almost all of the wine in the glass. Seconds later, the glass is somewhat more than half full.
Continuity: The detective accidentally throws his brandy over himself, soaking his shirt and jacket. In the next scene, seconds later, as he is about to leave the apartment, his clothes all appear bone dry.
Revealing mistakes: When Lisa comes to stay the night, she shows Jeff her tiny overnight case, which has barely enough space for her nightdress. Yet next morning she is wearing a whole new outfit.
Revealing mistakes: The Extakta camera used in this movie is usually held in a way that would suggest that the shutter is triggered on the right-side upward surface, as is normal for most cameras. 35mm Exakta cameras actually have the shutter release on the front of the camera, just left of the lens.