- Base-Breaking Character: Mr. Furley definitely has his fans, with some even adoring him more than the Ropers. However, some think the character is the catalyst to the show's Seasonal Rot. Others don't mind the character himself, and Don Knotts' performance, but find him out-of-place in the show.
- Fan-Preferred Couple: Many fans over the years have expressed disappointment that Jack and Janet didn't get together in the end. Ritter himself speculated that the sequel sitcom Three's A Crowd failed in part because fans couldn't accept Jack settling down with anyone but Janet.
- Harsher in Hindsight: A bumper from when the show aired on Nick @ Nite, called "Three Blonde Mates," featured the chorus joking about the revolving third roommate. Given the very cruel treatment of Suzanne Somers (Chrissy), Jenilee Harrison (Cindy), and Priscilla Barnes (Terri) by the producers it comes off as rather inappropriate.
- Hollywood Dateless: A mild example. It's strange when Janet complains about not having a date for the evening. She dates frequently but doesn't have a steady boyfriend through most of the series.
- Nightmare Fuel: In the episode "Dying to Meet You, Jack flirts with a woman who happened to have a jealous boyfriend who wanted to harm Jack but Jack had to pretend to be dead so the boyfriend will leave him alone, it is scary because the only way to get rid of the angry boyfriend, Jack had to lie in a coffin, which is pretty creepy.
- One True Threesome: Some people ship Jack/Janet/Chrissy.
- Replacement Scrappy: Cindy, Chrissy's cousin, was almost a carbon clone with considerably less jiggle factor and the added annoyance of being The Klutz. Terri managed to avoid this fate by actually having a brain.
- Retroactive Recognition:
- Actors who appeared on this show before gaining more notable work include Loni Anderson, Lauri Hendler, Joanna Kerns, John Larroquette, and Anne Schedeen.
- In addition to their work on Three's Company, developers and executive producers Don Nicholl, Michael Ross, and Bernie West are also best known as creators and executive producers of The Jeffersons.
- Don Nicholl is still well-known in the screenwriting community today, but not exactly for his writing. After he died in 1980, his widow Gee established the Nicholl Fellowships in Screenwriting in his memory. Now administered by the Academy of Motion Picture Arts and Sciences, it's far and away the most prestigious annual competition for amateur screenwriters.
- David Mirkin wrote seven episodes. Mirkin is best known as co-creator and co-executive producer of Get a Life, as well as the showrunner for The Simpsons's fifth and sixth seasons.
- Roger Shulman and John Baskin wrote four episodes and served as producers. Both are best known as creators and executive producers of Crazy Like a Fox.
- John Boni wrote three episodes. Boni is best known for co-creating When Things Were Rotten.
- Neal Marlens wrote two episodes. Marlens is best known as creator and executive producer of Growing Pains and co-creator and co-executive producer of The Wonder Years and Ellen.
- Joyce Burditt wrote an episode. Burditt is best known for creating Diagnosis: Murder.
- Howard Gewirtz also wrote an episode. Gewirtz is best known as creator and executive producer of Oliver Beene.
- Mark Fink also wrote an episode. Fink is best known as co-creator and executive producer of Hang Time.
- Prudence Fraser and Robert Sternin also wrote an episode. Both are best known as creators and executive producers of The Charmings and developers and executive producers of The Nanny.
- In the final four episodes, Janet's new husband was played by David Ruprecht who went onto host Supermarket Sweep.
- Seasonal Rot: The first three seasons with the original cast lineup are the most remembered, but season four (the first with Mr. Furley) has its fans as well. After Suzanne Somers left, the show's quality got progressively worse, with lazier writing and many recycled plots, and the characters Cindy and Terri being far less memorable than Chrissy.
- Tear Jerker: Mr. Furley recounting how he once had a pet as a kid, but it was hit by a car and died, he then decides to name the cat he found after it.
- Values Dissonance: The gay jokes on the show are a little hard to watch through a modern lens.
- What an Idiot!: This will apply to at least one character Once an Episode.
YMMV / Three's Company