In the episode "Rough Housing" near the end of the credits Arnold knocks over a cup off punch on the table, Willis instantly jumps out of the way and Kimberly wipes off her sweater. Photographic Evidence

In the episode "Emily Dickinson," when Mrs. Garrett is reading Blair's poem she says the lines "I don't like what I see" in the poem. Then when Blair says the lines "No, I deserve it. Go ahead, read the part about the 'soft cascading hair'." In these two lines, you can see a mole on Blair's left cheek near her nose as she stands by the grandfather clock. However, for the remainder of the episode the mole is no longer visible. The make-up artists have concealed in one frame, and it is completely visible in another! Also, when Blair mentions her 'soft cascading hair' oddly enough, her hair is moussier than any other time in the episode! Photographic Evidence 1 and Photographic Evidence 2

In the episode "Adoption," Blair states that Natalie's birthday is on November 2nd making her Virgo, but in the episode "Free Sprit" she mention to Alex that she is a Taurus.

In the episode "Adoption," while Blair looks at photos of Natalie's parents she states that both of them have red hair, but when we see them later in the series neither one of them do. Photo Evidence

Through out the second season and one time between scenes, Jo's clothing changes from a dark green shirt and a camouflage jacket to a camouflage jacket and a dark green jacket.

In the episode "The New Girl" (Part 1), Jo enters the cafeteria for the first time just seconds after we hear her drive up. Photographic Evidence 1 and Photographic Evidence 2

In the episode "The New Girl" (Parts 1 & 2), Jo enters the Chugalug bar with white open-toed shoes, but when we see her later in the jail cell she wearing black-closed shoes. Photographic Evidence 1 and Photographic Evidence 2

In the episode "The New Girl" (Part 2), while Jo is about to threaten to glue Blair's shoes together, Blair’s uniform tie goes from inside her vest to instantly outside her vest and back in again. Photographic Evidence 1 and Photographic Evidence 2

In the episode "Cousin Geri," Blair's cousin's last name is Warner but when she makes another appearance in the episode "Cousin Geri Returns" her last name mysteriously changes to Tyler.

In the episode "The Secret," while Blair is talking about Jo's Dad interest in the stock market, Blair's hair changes from straight to curled in the next shot. Photographic Evidence 1 and Photographic Evidence 2

In the episode "The Secret," Mr. Polniaczek's is written incorrectly in the ending credits. Photographic Evidence

In the episode "Bought and Sold," while Tootie and Blair begin to talk, Jo exits, and Natalie's shadow appears waiting to enter. Photographic Evidence

In the episode "From Russia with Love," Jo states that she has no living grandparents, but later in the episode "The Greek Connection," her grandfather visits her from Poland.

In the episode "Growing Pains," Mrs. Garrett locks the window, and in the next scene there is no lock on the window. Photographic Evidence 1 and Photographic Evidence 2

In the episode "The Four Musketeers," during the pain fight when Blair sits in the paint she has a smirk on her face, when she is supposed to be disappointed. Photographic Evidence 1 and Photographic Evidence 2

In the episode "The Four Musketeers," during the paint fight Blair shakes the paint roller instead of Jo’s hand. And begin laughing uncontrollably along with Natalie. Photographic Evidence 1 and Photographic Evidence 2

In the episode "New York, New York," while Jo is putting a suitcase strap around Blair's neck, in the background Natalie tries to hold in a laugh. Photographic Evidence 1

In the episode "The Sound of Silence," Tootie is leaving for the library and Mrs. Garrett says "I’ve never seen here like this," then you can hear an object on Jo's tray fall and then bends over to pick it up. Photographic Evidence 1 and Photographic Evidence 2

In the episode "Dearest Mommie," Blair is showing tricks with a yo-yo to Tootie, Jo and Natalie who are on the bed and when the yo-yo goes out of control they start laughing hysterically when they are supposed to be afraid.

In the episode "Help From Home," while Jo is putting on a Langley sweater her ponytail is insider her sweater, but in the next shot her ponytail is tucked outside.

In the episode "Next Door," before Mrs. Garrett and Danny come out you can see their shadows appear in the doorway, Mrs. Garrett even utters a wave while waiting for her que.

In the episode "Crossing the Line," after Blair and Jo depart after talking about their tips for each other, Blair accidentally hits Jo.

In the episode "Big Fish, Little Fish," where they show a shot the "Miss Edibles" sign has a picture of all the girls under it and their names, but under Jo's picture her last name is misspelled.

In the episode "Mother and Daughter," Tootie's mother is named Diane but later in the episode "Graduation" we find out her name is Pauline, she even makes an appearance in "The Facts of Life goes to Paris," movie and not as Tootie's mom.

In the episode "Crusin'," Blair talks about her friend being mad at her because Blair wouldn't invite her friend's fiancée to home-coming, and then later she says "She must be hard up for a date."

In the episode "Crusin'," while Jo is driving the car and accidently makes short stop while Blair is applying lipstick causing her to draw a long line of lipstick across her cheek while this is happening her hair several times during the course of the scence going from flat to teased.

In the episode "Taking a Chance at Love", when Jo is in love with her professor, he states that she is 19 years old, but according to Season 2 in actuality she should be 20.

In the episode "It's Lonely at the Top," near the end of the episode Jo open the cash register and there is no money in it at all.

In the episode "The Interview Show," Tootie states in an interview that she received her name while at her first year at Eastland, but in the first season episode "Overachieving," her father knowingly calls her Tootie.

In the episode "Cupid's Revenge," during the end of the scence where Blair and Cliff  are talking together on the sofa Blair's hair drastically changes from her curly perm into her straighter shoulder length style this happens almost back and forth.

In the episode "Tootie Drives," while Tootie is driving with Mrs. Garrett down the street in Eastland, there are palm trees far into the background.

In the episode "Atlantic City," Blair gambles at their hotel until we find out in the next episode "The Lady Who Came to Dinner" that they celebrate her 21^st birthday.

In "The Facts of Life Down Under" (Part 3), Beverly Ann mentions that her boyfriend will be picking her up in NYC, but earlier in "Off Broadway Baby," she states that she's never been to NYC.

In an episode, while Jo is telling her parents that she will not be attending college, the top button on her shirt is unbuttoned then goes to buttoned and visa versa almost between shots.