Revealing mistake: Judging by the interface, the video of Jenna and Toby sleeping together is played through Windows Media Player. When this program is playing a video, the big blue "Play" icon becomes a "Pause" icon. But whenever the video of Jenna and Toby is playing, the "Play" icon is still showing. It's obviously not an actual video being played.
Continuity mistake: When Jason first appears in the show he is played by Parker Bagley and is portrayed as a proper, motivated and well held, wide structured man, but disappears for a season or so, and is replaced by Drew Van Acker, and is now portrayed as a paranoid druggie, with mental health issues, and a lanky skinny structure.
Continuity mistake: When Aria's dad drops her off at school, the camera angle out the passenger window shows her wearing blue jeans. Once she's out, the camera angle changes and she's wearing black Levis.
Careful What U Wish 4 - S1-E14
Other mistake: During the scene after the fund raising dance when Lucas offers to take Hanna home, she calls him Ian when she says that she is going home with Emily and Spencer. Even if she says "I kind of promised them", the subtitles say Ian.
If at First You Don't Succeed, Lie, Lie Again - S1-E15
Continuity mistake: When Spencer and Emily are done eating pizza, Spencer stacks both their plates. However, when Emily storms off, the plates are unstacked again and now there is a napkin on her plate.
Continuity mistake: In the scene when Ezra rides up behind Aria in the Limo, you can see his hand up to his head, as if on the phone. The camera then cuts to Ezra in the Limo and you see him answer his phone. (00:22:25)
Continuity mistake: On the video of Ian supposedly killing Alison, we see her arm fall to the ground with her "Alison" bracelet visible. But in a later scene where Emily watches Ian put his bag in the athletics room, we cut back to the video and Alison's arm suddenly has a sleeve covering up her bracelet. When we see the video again later in the series, her bracelet is visible again.
Factual error: Emily is supposed to meet Paige at a karaoke bar at the intersection of 202 and W. Chester Pike, however this intersection is actually an overpass. 202 crosses over top of West Chester Pike, but never actually intersects it.
Someone to Watch Over Me - S1-E20
Continuity mistake: After Jenna is slapped by Hanna in the bathroom a single tear streams down her right cheek. The next shot of Jenna shows the tear track on her left cheek.
Picture This - S2-E9
Continuity mistake: When Hanna and Caleb are sitting on the swings in the park, the first part of the scene shows nothing in Caleb's lap. However, when it cuts to them holding hands, a pizza box appears. (00:29:10)
Touched by an 'A'-ngel - S2-E10
Revealing mistake: At the end of the episode, Emily receives a phone call from Dr. Sullivan which she does not answer. Look at her phone when she hangs up: Not only does she simply press the "hang up" icon when the arrow indicates she needs to slide it to the left, there is also a magnifying glass symbol at the bottom indicating that it is in fact an image file on the screen and not an actual phone call.
Continuity mistake: Mrs Sullivan circles "nosey bitches" on a paper (someone's file) and the circle is overlapped at the bottom. When the camera moves out the circle changes and is disconnected from the top instead.
Through Many Dangers, Toils, and Snares - S2-E14
Continuity mistake: When Emily circles the word "yes" on the chalkboard, the way the circle is drawn changes between shots.
The Blond Leading the Blind - S2-E17
Continuity mistake: In the flashback to the Halloween party where Alison finds the note from A and removes it from the knife, she is either holding the knife upwards or downwards depending on the shot.
It Happened 'That Night' - S3-E1
Character mistake: Emily's mom tells Emily that reporters were there to talk to them about "Emily's missing remains." It's supposed to be "Allison's missing remains." (00:17:00)
Blood Is the New Black - S3-E2
Continuity mistake: When Ezra is talking to Aria's mom in the classroom, she is writing on the chalkboard. After a brief moment, she is erasing information on the board, and we see it gone, but Moments Later the writing is back on there.
Continuity mistake: When Spencer and Toby are having lunch, she lifts her water bottle. Between shots, the hand she is using changes. (00:46:35)
Cat's Cradle - S4-E3
Continuity mistake: When Hannah is on the phone to Emily, Hannah pours a glass of fizzy drink (coke or whatever) and is about to drink from the glass, in the next shot she takes the can and walks away and the glass isn't seen again.
Continuity mistake: When Emily and Aria are contemplating climbing out of the window and down the trellis to get help, they hear Alison scream and the broken window slams down completely; the shot briefly changes then the window is shown half-way up.
Shadow Play - S4-E19
Other mistake: When Ezra takes Spencer's file from the school he takes it from section A-E. Neither of Spencer's names fit into that category.
