The Patty Duke Show was an 1963–66 Dom Com on ABC, starring Patty Duke as identical-looking cousins Patricia "Patty" Lane and Catherine "Cathy" Lane—one American and one Scottish—both of whom live with Patty's family in Brooklyn Heights, New York.
This series provides examples of:
- All Elections Are Serious Business: Patty and Cathy are talked into running for president of the Girls' League, an organization at their high school. The ensuing campaign comes complete with mudslinging and the cousins stealing both voters and campaign ideas from each other.
- Alpha Bitch: While multiple female classmates could count as this to Patty, the most notable example was Sue Ellen, who even served as the villain of the Reunion Show.
- Always Someone Better: The flashbacks in "The Cousins" (actually taken from the unaired pilot) have Patty being compared to Cathy, once while Patty masqueraded as Cathy and again vice versa; even driving Patty to tears.
- Artistic License – Biology: Patty and Cathy's Uncanny Family Resemblance is explained away as the result of a pair of identical twin brothers marrying a pair of identical twin sisters, i.e. Patty's father's identical twin had married Patty's mother's identical twin.
- Badly Battered Babysitter: Patty in The Babysitter, her hair and outfit end up messed up, but she and Cathy were able to turn tables on the Bratty Half-Pint.
- Beware the Nice Ones: Cathy is a demure and proper young lady, however, you don't insult her Father to her face nor mess with her cousin as a babysitting client and an obnoxious aunt found out.
- Bottle Episode: A lot of these, though in this case it's split-screen photography and not location filming that is being avoided. Despite the identical cousins being the premise of the show, there are a lot of episode which don't have Cathy in them at all (or her in one scene where Patty isn't present).
- Bratty Teenage Daughter: Patty is this trope, of course she is referred to as an average American teenage girl, yet her brattiness and her one-track mind make her a more comedic version and she is the protagonist.
- Breaking the Fourth Wall: At the end of Season 1, Episode 15, "The Christmas Present," Patty steps out of character to invite the audience to tune in next week to witness the resolution to this week's conflict, and to wish the viewers a Merry Christmas.
- Candy Striper: Season 3, Episode 12 "Patty, the Candy Striper" sees Patty bumbling her way through her usual Candy Striper duties as she tends to her father, who is stuck in the hospital.
- The Ditz: Patty's long-suffering boyfriend Richard drifts pretty near to this. It's no wonder she always seems to be on the lookout for a better option.
- Double Standard: As the series goes on, Patty really shows no loyalty to Richard at all, but he always comes back to her when she'll have him.
- Double Vision: Here's to you, Rita McLaughlin, whose back and shoulder went uncredited for decades...
- Dumbass Teenage Son: We don't see a lot of Richard's parents, but he is dimwitted enough to serve as one, as far as Martin Lane is concerned.
- Expository Theme SongMeet Cathy, who's lived most everywhere,
From Zanzibar to Berkeley Square,
But Patty's only seen the sights
A girl can see from Brooklyn Heights,
What a crazy pair!
But they're cousins,
Identical cousins all the way,
One pair of matching bookends,
Different as night and day
- Extreme Doormat: Cathy, to the point where Patty once convinces her to do Patty's half of the chores so she can "study" rock 'n' roll and where she ends up buying a vacuum cleaner from a pushy salesman that she has no money for.
- Genki Girl: Patty is a high-energy teen who jumps from thing to thing, maybe with a little more focus than average for the trope.
- Housewife: Natalie is a more realistic example of the stay at home mother, as that she can be harsh with her children and can snark at her husband despite being sweet. The first season episode "Are Mothers People?" explores how she can feel under-appreciated by her family, even by the usually sweet and considerate Cathy and Mr. Lane.
- Interpol Special Agent: Subverted when a British guy from Interpol appears in one episode, and Patty assumes he's on some James Bond secret mission, and he's not.
- Jerkass Ball: In "Are Mothers People?", Mrs. Lane is feeling under-appreciated by her family, and with good reason; while it's not unusual to see Ross and Patty as self-centered, Mr. Lane and Cathy are unusually inconsiderate of her. It doesn't last long thankfully.
- Men Can't Keep House: Patty has a nightmare of being married to Richard where she works and picks up everything while he lies in bed reading comic books.
- Mirror Routine: Done by Patty and Cathy in the pilot episode. The scene was then used in the opening credits.
- Unlike most other examples of this trope, however, an actual mirror was used - you can see the bottom of it in the opening credits if you look carefully - given that it was one actor instead of two.
- Ms. Red Ink: When Richard has a nightmare about being married to Patty, he dreams that she lounges around in her bed on the phone and that she'd be spending a lot of money on mink coats.
- Not Allowed to Grow Up: Paul O'Keefe as Patty's little brother Ross experiences a quite visible growth spurt toward the end of the series, but the character is still written mostly the same way. They did allow him to start showing a tentative interest in girls, but it still feels a bit late considering how tall he is and how deep his voice has gotten by then.
- Not Even Bothering with the Accent: Patty Duke originally worked to master an authentic Scottish accent for Cathy, but the show's producers — afraid that American audiences would be put off by a thick burr — convinced her to use a milder "mid-Atlantic" accent for the character instead.
- Nuclear Family: The Lane family with a newspaper editor father, Housewife mother, Bratty Half-Pint Annoying Younger Sibling Ross, Bratty Teenage Daughter Tv Teen Patty, and Nice Girl Cathy. This trope is played with more than most, as Cathy is a cousin living with her aunt and uncle; and while they don't fit the Dysfunctional Family model yet were more realistic than most families of that era or later with usually nice and competent Parents as People who love and make snarky comments to their kids.
- Parents as People: Martin and Natalie Lane are terrific parents, but they're not afraid to scold and snark at their kids or argue with one another.
- Pie in the Face: Patty falls victim to this in "The Perfect Teenager" during a modeling session, in which she's humiliated in various ways.
- Pilot: Set in San Francisco rather than New York, and featuring different actors for Patty's father and brother. It never aired, although parts were eventually incorporated into the Season 1 finale "The Cousins".
- Plot Allergy: In "The Friendship Bit", Patty starts sneezing whenever she's near Cathy. Her parents think she's developed a psychosomatic allergy to her cousin because she's jealous of her. But it turns out she's really allergic to a new pin Cathy has been wearing.
- Polar Opposite Twins: Unbuilt Trope, as they're identical cousins, and former Trope Namer.
- Poor Communication Kills: The plot of "Are Mothers People?"
- Rearrange the Song: For the show's third and final season in 1965, the show's theme song was altered to a bouncier, rock-'n-roll-oriented arrangement, punctuated by a memorable electric-guitar riff.
- Shoo Out the Clowns: The episode "Do You Trust Your Daughter?" stands out for having no laugh track, and comical characters such as Richard are nowhere to be seen. It's a notably serious episode in which Patty and Martin fight over the former's questionable responsibility.
- Standard '50s Father: Martin Lane was hardly infallible, but he was a very understanding dad, and generally one of the most likable examples of the trope.
- Twin Switch: Patty and Cathy, and vice versa.
- Uncanny Family Resemblance: The Trope Codifier.
- Vocal Evolution: Between Seasons 1 and 2, puberty hit Paul O'Keefe like a meteor. Ross not only got taller than Patty, but his voice got deeper.
- Wunza Plot: To the show's credit, while it unquestionably fits this trope, it subverts it in that really only a small percentage of episodes deal directly with Patty and Cathy's resemblance. In practice, the gimmick is mostly just an excuse for Patty Duke to play two distinct roles—which she does skillfully.
- You Called Me "X"; It Must Be Serious: 99% of the time, Patty calls her father "Poppo." When she's upset or has a problem, she calls him "Daddy."
- Plus when she's in trouble with her parents, she calls him "Father."
- Zany Scheme: Patty comes up with them frequently.