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.
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.
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.
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.
Revealing mistake: After the flashback to when the girls first met Cece at The Brew, she looks at them through a window outside when she leaves. If you look closely at Cece's hair, you'll notice a green glow, revealing that she's on a green screen. This explains why the image of the girls through the window doesn't look quite right. Cece is also wearing a different dress.
Through a Glass, Darkly - S5-E14
Revealing mistake: When Jason shows Ali the family photo you can see that Jason and Ali have been badly, almost cartoonily photoshopped in.
No One Here Can Love or Understand Me - S5-E11
Continuity mistake: In the beginning of the show, when Emily and Spencer are at the brew, they are seen holding a blue mug filled all the way with whipped cream. Pay attention to Spencer's mug; the amount of whipped cream changes between shots.
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.
Continuity mistake: When Spencer beats Detective Furey at ping pong, he throws his paddle down on the table in frustration. The paddle then immediately moves to a different position in the next shot.
To Plea or Not to Plea - S5-E22
Revealing mistake: When Emily calls Varjak's number from the Tony's Pizza receipt, her phone says that it has no service - meaning she should not be capable of making any calls.
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)
Continuity mistake: When Hanna and her mum are in the kitchen talking about Hanna's dad and the beauty pageant, Hanna's phone keeps flipping over on the kitchen counter throughout the scene.
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.
In the Eye Abides the Heart - S7-E15
Continuity mistake: After Paige asks Alison if she loves Emily, the hair on Alison's right shoulder moves a few times between shots without her touching it.
Continuity mistake: When Mrs. Hastings is on the phone abut the tree in the garden, her phone is not in call mode.
Revealing mistake: When Emily gets a phone call from Spencer, the answer button is still visible when she puts the phone to her ear, meaning the phone should actually still be ringing.
Pretty Isn't the Point - S5-E20
Continuity mistake: The pizza slice that Hannah is eating when her mum starts talking to her and Emily in the kitchen jumps back onto her plate between shots. Her arms are also suddenly folded.
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.
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)
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.
