Visible crew/equipment: In the scene where Frank humiliates Dorothy and Jeffrey watches from inside the closet, you can see someone walking out of the bathroom. This happens right after Frank leaves and before Jeffery steps out of the closet.

Continuity: In the first of the nightclub scenes in which Dorothy Vallens is seen singing 'Blue Velvet' her dress mysteriously changes from having straps to a halter top. The 'why' for this becomes clear later in the film - in her second nightclub appearance (the following day) she is wearing the halter top. Evidently the filmmakers cut in a shot filmed for the second scene.

Factual error: Right before Frank humiliates Dorothy for the first time, she blows out one of the gaslights in her apartment. That is never done in real life, for the same reason you would not blow out the pilot in your stove.

Continuity: At Ben's place, Frank enjoys a cold glass of Pabst Blue Ribbon - its colour, the level in the glass, and the amount of head change repeatedly within a few seconds.