Continuity mistake: When Will and Grace are standing outside Will's apartment, after Grace arrives back from her honeymoon, Grace is holding a handful of photo envelopes. Between shots the way she holds these envelopes changes.
Continuity mistake: When Jack is trying to hush the audience at his show Jack-Talk after bringing Grace onto the show for a follow-up interview, between shots the little bell on his desk moves from his right (near the edge) to over past his left, near the centre of the desk with all the other items. (00:15:55)
He Shoots, They Snore - S4-E21
Continuity mistake: When Grace is setting up her design class, she writes "Professor" on the board, and curls the end of the R into a spiral. But in the shot when she says "T.A. - Teachers Assistant" the spiralled end on the R has gone. In the next shot it's back again. (01:04:40)
With Enemies Like These - S11-E3
Continuity mistake: Sharon Timmer introduces herself to Grace in Series 10 Episode 1: "I've lived directly below you for 19 years." But then in Series 11 Episode 3 she seems to live in Flat 9B next door to Will and Grace. I'm not sure we've ever seen who lives there before, but guessing by the layout of Will and Grace's flat, there wouldn't actually have been space for an extra flat in that space. (00:00:16 - 00:12:12)
The Things We Do for Love - S10-E17
Continuity mistake: While Will and Jack are sitting at the table having a conversation, the mugs monogrammed "W" and "G" from which they are drinking tea magically switch between them several times. (00:06:30)
There but for the Grace of Grace - S2-E21
Continuity mistake: When Will and Grace are sitting at the dining table discussing how much like Sharon and Joseph they are, the napkins on the table change shape and move around a bit, and one ends up with a plate underneath it just before Will picks it up.
Continuity mistake: The art show is supposed to take place at the Zelman gallery and inside there is a sign that says that, but the establishing shot shows that the name is the Phyllis Kind gallery.
Continuity mistake: Grace stumbles right after Karen says "Do you know how humiliating it was for me to have to finish myself off in front of your father?" but immediately in the next shot she does it again.
The Blonde Leading The Blind - S7-E20
Continuity mistake: In this episode, Karen doesn't want to get glasses because she thinks they make her look old. However, in a previous episode (S1E9) we see that she actually already wears glasses. In a scene where Jack asks her to read his script, she quickly puts on a pair of reading glasses.
A Little Christmas Queer - S8-E9
Continuity mistake: Shortly after arriving at their mother's house, Will's brother, Sam, nervously excuses himself from a conversation with Grace. "Excuse me," he says, "I have to go get a ladder. There's a couple of bulbs out in front, and now it just says 'Happy Ho-days.'" However, exterior shots of the front of the house show no holiday lights whatsoever.
Marry Me a Little More - S5-E9
Continuity mistake: When Karen goes into the room to speak to Grace before she gets married, Karen's feather boa is on her shoulder, off her shoulder, on her shoulder...
The Finale - S8-E23
Continuity mistake: In the shots of the dorm hall showing Ben and Lila moving into their rooms, the two cardboard boxes outside Ben's dorm keep switching which one of them has writing on it. (00:31:25)
The Finale - S8-E23
Continuity mistake: In Will and Grace's apartment, as Jack stands up to announce his news about Beverley, Will and Grace are cutting slices of cake and putting them on plates. In the next wide shot Karen (who is sitting on the sofa, away from them) had a plate with a slice of cake and a napkin, before Grace had even handed Jack any plates! (00:21:00)
The Finale - S8-E23
Continuity mistake: Nearing the end of the episode, when Karen and Jack are sitting reading magazines, as Karen asks Jack a question, the way she holds her reading glasses changes between shots. (00:35:00)
The Finale - S8-E23
Continuity mistake: When Leo opens the door and finds Grace sitting at the table eating chicken, the scrunched up ball of tissue on the table next to the plate disappears in one shot. (00:07:45)
The Finale - S8-E23
Continuity mistake: When Beverley Leslie is talking to Jack in the restaurant about him being his "associate", the napkin on the table which Karen left behind changes position a few times. (00:17:10)
Whatever Happened to Baby Gin? - S8-E22
Continuity mistake: When Karen is sitting with her sister Gin at the table in the bar, throughout the whole scene Gin's black purse and the bar menu she has continually change places. In some shots she holds the menu and the black purse is on the table. In some shots the menu is on the table and the purse is on her lap. And in some shots both items are on the table. (00:05:45)
Continuity mistake: When Will and Grace are at the Lamaze class and are introduced to the basket full of plastic baby dolls, the positions of the dolls in the basket changes between shots. (00:10:25)
Continuity mistake: When Karen and Jack hug at the end of the episode, Karen's hands are empty as they embrace. But in the next shot she instantly has a drink in her left hand which she walks away with. (00:20:05)
Continuity mistake: When Will pulls down the chart which is recording Grace's pregnancy patterns, he draws a red cross in a box. In the following shots the appearance of the cross keeps changing between two obviously different crosses (from two takes edited together.) (00:14:25)
