Plot hole: In the episode "Lows in The Mid-Eighties" during the flashback scenes, it is shown to us that Will comes out of the closet during his freshmen year of college during Thanksgiving Break, when they spend the weekend at Grace's Parents house. However in the episode "Willian, tell" Grace claims that Will came out to her at senior year of college during Christmas Break. Quite a difference for such a memorable time.

Plot hole: The apartment block where Will lives supposedly has the same layout for each floor of the building. Yet in "Yours, Mine or Ours" the room 12D is seen as located right in front of the elevator, the same location as Will's apartment door - however Will's apartment is always seen as 9C.

Plot hole: In earlier episodes, the hallway outside of Will's apartment does not match up with the layout of his apartment. Also, the board outside, besides the lift shows inconsistencies in the layout of the whole building.

Plot hole: In "Alley Cats" when they are bowling and Grace is losing, she says she's fine with it and she knows how it feels to be her middle sister, then Will reminds her that she's actually, "The baby of the family looking for Daddy's approval." However, in all later episodes, Grace is portrayed as the miidle child with a younger sister, Joyce and an older one called Janice. This mistake is made in a few other places through the show, where Grace either refers to how old she is (youngest, middle child etc) incorrectly.

Continuity: When Jack holds his glass of water, he changes from holding the stem of the glass, to the actual bulbous part of the glass between shots.

Plot hole: Ellen and Rob wear wedding rings, yet their wedding is not announced until "An Affair to Forget" in the second season.

Continuity: As Will talks to Grace in his office, near the end of the episode, Grace is still in her wedding dress and the position of the veil keeps changing.

Visible crew/equipment: As Will gets a drink from the fridge, you can see the boom mike above him, following him as he walks around, to pick up his audio.

Visible crew/equipment: The shadow of the boom is cast on Will when he says "Let's play the Pyramid!"

Continuity: When the guys are playing poker, the chips and cards on the table move about.

Continuity: When the guys are playing poker, Jurgen picks up his beer bottle and starts to drink, but in the next shot it's suddenly back down on the table.

Continuity: In the poker scene at the beginning of the pilot we witness Will, Jack, Rob, and others playing cards. Shortly after Jack asks for "four cards please" watch the bottom left of the screen as a hand (presumably Will's) deals Jack a single card. In the next shot Will appears to have not dealt Jack any cards yet and when he does he gives Jack five cards, add that to the single card he gave in the previous shot and the Ace Jack kept from his original hand and we get a total of seven cards. Two more than Jack should have had if the hand was dealt correctly.

Continuity: Following the argument between Will and Grace when she returns from City Hall, Karen tells Grace she "thinks it's time for a couple of blue bibbies." Watch closely as she removes the lid from the pill bottle, takes out some pills, and puts the lid back on. The scene shoots to Grace and we hear Karen shaking the closed bottle. When the scene shoots back to Karen we see that the pill bottle is open again and Karen closes it yet again.

Continuity: When Will and Grace are at the bar, right at the end of the episode, Grace’s wedding dress is up on the bar-side, but in the next shot it is off of the bar.

Continuity: When Jack enters Will's apartment for the first time, with the idea of him moving in, the exterior outside of Will's apartment is completely different that for the rest of the whole show, and there's a wall right by his door.

Continuity: When Grace finally decides to move into Will's apartment near the end, we see Will eating a tub of ice cream. Between shots the ice cream tub lid jumps from being on the table behind Will, to suddenly sitting right in front of him.

Continuity: When Karen is sorting out her clothes at her work desk, the black sweater hanging over the desk lamp disappears then reappears.

Continuity: When eating in Will’s office, Grace eats salad from a plastic container. Through the scene the salad in the container changes colour, position etc. Also between shots, lettuce appears on Grace’s fork.

Continuity: After Karen takes her black top off and throws it down on the table, whilst talking to Jack as they first meet, in following shots the top changes position a few times.

Visible crew/equipment: When Grace asks Will for his advice on where her mirror in her new apartment should go, she goes running to the wall and when she does, the camera pans over and you can see that the wall stops, revealing it to be a set.