The third season of The Wonder Years aired on ABC from October 3, 1989, to May 16, 1990.
 In the remaining days of summer, the Arnolds decide to take a vacation trip to Ocean City, in part for old times' sake, since it was Jack and Norma's honeymoon destination. Paul comes along, but the vacation turns out to be a disaster, as Paul gets car-sick and throws up a couple of times and later appears to get sunburned but actually develops an allergic reaction to fish he ate, which forces him to stay inside for the remainder of the week-long vacation; add to that Wayne's constant bullying, Karen's belly-aching and complaining, and Jack's constant complaining about the high prices. So Kevin, now feeling more alone than ever, decides to take a stroll along the beach in search of a little solace, where he encounters Teri (Holly Sampson), a beautiful (although older) girl who also seems alone, but more upbeat and optimistic. Kevin and Teri plan a date to the boardwalk arcade the next day. Their date ends with a kiss under a pier, but the moment is ruined when Teri turns down a second date for the next day, because she and her family got called back home to Albuquerque due to her father's job. Teri promised to write to Kevin every so often until they met again; but after only one letter, Kevin never heard from her again.
 As Kevin begins eighth grade, he finds himself struggling in math and quickly has trouble understanding it receiving 39 on a state mandated math test. But when his very strict math teacher Mr. Collins (Steven Gilborn) offers him a study group after class, Kevin refuses when he sees the group is composed of the dumbest kids in school. Kevin then receives bad grades on pop quizzes and fails a test. Eventually, he must tell his dad about the situation and he starts to turn things around.
 Guest-starring: Steven Gilborn in his first appearance as Kevin's math teacher Mr. Collins.
 Wayne gets his driver's license but reluctantly has to chauffeur Kevin and Paul to the mall. While there, Kevin meets his "dream girl" (Jennifer Barron) whom he follows to the movie theater where Romeo and Juliet is playing. When Kevin finally gets his chance to introduce himself and talk to her, Wayne shows up and embarrasses him by driving away every time he reaches for the door handle.
 Guest-starring: Jennifer Barron as Kevin's unnamed "dream girl" (his mall crush).
 Recurring guest: Juliette Lewis as Delores.
 Against his mother's wishes, Kevin decides to play "no-equipment" football in Shepherd's Park with his friends after school. After finding blood on his shirt, Norma (Alley Mills) tries taking Kevin clothes shopping to distract him from playing, but it backfires. Kevin soon realizes that this game is dangerous when he gets hurt while being gang tackled. Kevin finally gets what he wished for when Norma stops babying him and tells him to bandage the wound himself.
 Guest-starring: Sean Baca in his first appearance as Craig Hobson; Brandon Crane in his first appearance as Doug Porter; Michael Tricario in his first appearance as Randy Mitchell.
 The new dramatic arts teacher Mr. Weber (Nicholas Hormann) is holding auditions for the school play Our Town, where Winnie and Paul audition. Paul is rejected while Winnie gets the leading role of Emily Webb, whereas Paul becomes heartened when he works on the crew alongside Kevin, who sees it as a chance to get out of gym class. When Paul falls ill, it's up to Kevin to run the spotlight, which he awkwardly does until Winnie's moving performance inspires him to realize the importance of being on a play's crew, and leads her father to move back in with her and her mother.
 After a heated argument over their elusive Willie McCovey baseball card trade, Kevin and Paul choose new best friends. Kevin hangs out with Doug Porter, and initially it goes great, but eventually he finds Doug too passive, and Doug eventually prefers to hang out with Paul's new best friend Brady Ryland. Kevin and Paul realize they missed each other's companionship. 
 Guest-starring: Marty Belafsky as Brady Ryland.
 Recurring guest: Brandon Crane as Doug Porter, who was originally intended as a one-shot character, but impressed the producers that they gave him a recurring role where he is shown as a friend of both Kevin and Paul.
 The Arnolds notice one of their neighbors driving home a new car, while the Arnolds' family station wagon just isn't roadworthy anymore; so in "keeping up with the Joneses," they decide to buy a new car, too (after Norma pressures Jack into doing so). The Arnolds then visit a car dealership and, at the persuading of salesman Marvin Lutz (Patrick Cronin)--and the kids--Jack selects a new cherry-red '69 Ford Mustang convertible and is ready to seal the deal. However, Jack blows up and backs out of the deal when he thinks Lutz didn't offer him a fair trade-in value for their old car. Meanwhile, Jack decides to fix up and wash the station wagon and put it up for sale. But when Jack informs prospective buyers of his price, they walk away laughing, thinking the price is outrageously high--which leads to Karen offending her father by calling him "cheap." However, in the end, the Arnolds do end up buying a new car, but it's not the Mustang. It turns out to be a 1969 Galaxie 500. As the station wagon ends up being towed away to the junkyard, Kevin has memories of road trips and realizes why it was so hard for his father to dispose of the car. With the neighbors admiring the Arnold's new Ford, Kevin said it was the Arnolds' turn to be "king for a day".
 Guest-starring: Patrick Cronin as car salesman Marvin Lutz.
 Kevin gets his first pimple a few days before family friends, the Pruitts and their beautiful daughter Gina (Heather Green), come for a visit. As he desperately tries to get rid of his pimple, Kevin goes as far as paying Wayne for his zit cream to covering it with a band-aid and telling Winnie he got into a fight with school bully Tony Barbella (Tony Nittoli). Unfortunately for Kevin, none of these tactics work, and Kevin must face the music—and the Pruetts—with his pimple, only to discover that coincidentally Gina had developed her first pimple, too.
 Kevin overhears classmate Eddie McCormick (Chris Demetral) having a conversation with two others about cheating in his math class. After being graded on a curve because of the cheaters, Kevin decides he wants in and asks Eddie "How 'bout those Mets," the secret code that he's on board. As a result, his grades rise to near perfect and he is put in the honor math class. While McCormick and his cohorts flunk an exam, Kevin feels he is punished with this new class. Mr. Collins (Steven Gilborn) offers Kevin to revert to his old math class and keep his grades up.
 Guest-starring: Chris Demetral as Eddie McCormick.
 Recurring guest: Steven Gilborn as Mr. Collins.
 After helping the new student from San Francisco, Larry Beaman (Joshua John Miller), get out of trouble with vice-principal Diperna (Raye Birk) when he's not allowed to play his guitar on school property, Larry teaches Kevin how to play guitar. Inspired by The Beatles, they form a rock 'n' roll band called the "Electric Shoes" and land a gig at an 8th-grade birthday party for Amy Ermin (Stefanie Scott), but are forced to stop playing by her father (Ben Slack) and the police because they're too loud.
 Guest-starring: Joshua John Miller as lead guitarist Larry Beaman; Casey Ellison as drummer Mark Bernstein; Dana Young as bassist Neal Rhodes; Stefanie Scott as Amy Ermin; Ben Slack as Amy Ermin's father.
 Both being dateless for the upcoming school dance, Kevin and lab partner Linda Sloan (Maia Brewton) agree to go to the dance "as friends." But soon after, Kevin's latest crush, a girl with a Southern accent named Susan Fisher (Kelly Packard), asks him to save a dance for her. This now puts Kevin in a predicament as he is now torn between Susan and Linda as to whom to spend more time with at the dance. Kevin lets Linda dance with Steve Padway (Andy Howard), a boy who has a crush on Linda, while Kevin dances with Susan; but Kevin unfortunately has nothing to have a conversation with Susan about afterwards and she therefore finds her ex-boyfriend Donald Wallach (Sean Wohland) and they get back together. Noticing the attention Kevin had been giving Susan, Linda becomes offended and leaves Kevin standing alone at the punch bowl. Meanwhile, after a short break-up, Paul and Carla get back together, now making Kevin feel totally left out. Now alone, Kevin searches for another free girl to dance with. Coincidentally, it just so happens that Winnie shows up at the dance, also dateless. But unfortunately, while searching for dance partners, both Kevin and Winnie miss seeing each other and Kevin finally leaves the dance.
 Guest-starring: Maia Brewton as Linda Sloan; Kelly Packard as Susan Fisher; Andy Howard as Steve Padway; Sean Wohland as Donald Wallach.
 Recurring guests: Krista Murphy as Carla Healey; Ben Stein as Mr. Cantwell.
 Grandpa Arnold (David Huddleston) visits the Arnolds, bearing gifts. One is a surprise for Kevin—a puppy; but Jack forbids it, thinking that Kevin can't handle the responsibility of taking care of a pet. But after a heated argument between Jack and Grandpa, Jack decides that a dog is exactly what the family needs and asks Kevin to keep him.
 Guest-starring: David Huddleston in his first appearance as Grandpa Arnold; Gary Grossman as Kevin's biology teacher Mr. Corey. 
 When Paul gets dumped by Carla, Kevin wants to help his brokenhearted friend get his self-confidence back. While he helps Paul think of other available girls to date, Kevin is stunned to discover that Paul is interested in dating Winnie, but Paul is shy about asking her out because he feels awkward about dating his best friend's ex. So to ease the pressure for Paul, Kevin coaxes Winnie into asking Paul out on a date; but after going out three times, things take an unexpected turn when Paul actually starts falling for Winnie, making Kevin jealous. Winnie doesn't feel the same way about Paul and tells him she still likes Kevin, but wants to keep it a secret. However, Kevin finds out and goes to Winnie's to tell her that "he knows she's crazy about him," only to get the door slammed in his face. Part one of two. 
 Recurring guests: Krista Murphy as Carla Healey; Robert Picardo as Coach Cutlip.
 Absent: Alley Mills as Norma Arnold; Olivia d'Abo as Karen Arnold.
 Things get complicated for Kevin when his please-forgive-me valentine meant for Winnie ends up by mistake in the locker of Becky Slater who, because of it, wants to rekindle their short-lived romance. But Kevin informs Becky that the valentine was not meant for her, making her mad at Kevin once again. Therefore, Becky seeks revenge by trying to run Kevin off the sidewalk with her bike; but Curtis Hartsell (Fred Savage's younger brother Ben, playing the role of Cupid) winds up in Becky's path, causing her to crash into Craig Hobson, making a love connection. Kevin seeks advice on love from Mrs. Heimer (the former Miss White) and she tells him to speak from the heart which he does to Winnie, finally confessing that he likes her. Part two of two.
 Guest-starring: Ben Savage as Curtis Hartsell; Elyse Eberstein as Winnie's friend Melissa Bemil; Jean Palmerton as Kevin's art teacher Mr. Dougherty.
 Recurring guests: Crystal McKellar as Becky Slater; Wendel Meldrum as Mrs. Heimer (nee White); Sean Baca as Craig Hobson.
 After seeing a shocked look on his friend Doug Porter's face after he receives "the talk" from his father, Kevin wonders when his time will come. Meanwhile, Jack has a week off from work, and he has nothing to do around the house but repairs, which upsets the balance of Norma's household. So Norma suggests that he and Kevin build a tree house together. Jack lets Kevin help by allowing him to use his power tools and things run smoothly until they go up on the platform to look at the view of the neighborhood. The elevated platform also allows them to catch a glimpse of their voluptuous neighbor Donna (Janet Wood) singing while working her tomato garden. This causes Jack and Kevin to share an awkward moment, especially when Norma invites Donna over for a visit. Norma eventually decides to check on their progress and sees the same view of her neighbor, which makes Norma a little uncomfortable. Channeling Norma's response, Jack then has a different talk with Kevin and admits that he's too old for a tree house after all, which stops the construction altogether. In the final scene of the episode, the platform of the incomplete tree house starts to collapse.
 Guest-starring: Janet Wood as the Arnolds' neighbor Donna.
 Recurring guest: Brandon Crane as Doug Porter.
 When Kevin's music teacher Mr. Frace (William Lanteau) turns his class over to perky and optimistic student teacher Miss Haycock (Andrea Walters), the untalented, terrible-voiced eighth grade glee club rehearses "Stout-hearted Men" for the Spring Sing concert. But after Kevin and the rest of the class tells Miss Haycock they don't want to sing in the concert, she breaks down in tears; but classmate Warren Butcher (Jeffrey Baum), who up until that point never even talked, begins holding a note in perfect pitch, and sings with perfect vibrato when they rehearse the song again, with the rest of the boys singing better. Now the glee club has a secret weapon for the concert--until the night of the concert when Warren's 13-year-old voice starts to change shortly after the beginning of the song, causing a disaster including Paul sneezing out of control and Doug falling off the stage. The glee club then limps through the rest of the song; and when the song is over, a dejected Miss Haycock wanders offstage, never to be heard from again.
 Guest-starring: William Lanteau as Kevin's original music teacher Mr. Frace; Andrea Walters as student music teacher Miss Haycock; Dustin Diamond as Joey Lapman; Troy Slaten as Eric; Jeffrey Baum as Warren Butcher.
 Recurring guests: Brandon Crane as Doug Porter; Michael Tricario as Randy Mitchell.
 Since Kevin and Winnie are a couple once again, they get invited to a make-out party hosted by infamous ninth grader Robbie Hudson (Greg Davis). When Kevin goes to the Cooper house, he thinks he will be attacked, only for Mr. Cooper to receive Kevin warmly (under the impression Kevin and Winnie are going to a friendly social). When they get chosen to go into the make-out room, things get awkward for the young couple, especially when Winnie doesn't want to kiss Kevin, leaving him confused. Later that night, Winnie comes to Kevin's bedroom window while he's sleeping and asks him to go for a walk so she can explain herself. But Kevin thinks Winnie wants to be just friends again--until she calls him her boyfriend and kisses him on a bridge. Turns out that Winnie was only waiting for the perfect moment!
 Guest-starring: Greg Davis as Robbie Hudson.
 Recurring guests: Crystal McKellar as Becky Slater; Krista Murphy as Carla Healey; Sean Baca as Craig Hobson; H. Richard Greene as Mr. Cooper; Ben Stein as Mr. Cantwell.
 It's tax time, but Norma loses the tax receipts needed for filing, and the family awaits their impending doom when Jack finds out. But they learn that there are more tragic things happening in the world. The news broadcasts of the failed Apollo XIII space mission has everyone on edge, so Norma goes to a church to pray for the missing astronauts. In a subplot, Mrs. Stebbins (Salmone Jens), Kevin's English teacher, gives his class an assignment to write an obituary of their lives for creative writing, but Kevin can't decide how his life will turn out in the future in order to write an acceptable obituary. 
 Guest-starring: Emily Schulman as Susan Kelly; Josh Berman as Harold; Billie Joe Wright as Larry; Michael Bower as Joe; Salmone Jens as Kevin's English teacher Mrs. Stebbins.
 When Paul tries out for the Kennedy junior high Wildcats baseball team, Kevin gets the coach's attention when he instructs him at bat. Coach Ted Baker (Harrison Page) asks Kevin to come up to bat and he smashes a line drive to right field, impressing him so much he asks him to try out for the team. But Kevin wonders why he keeps making the cut even though his performance is bad and wants to know why. He finds out that Coach Baker is his father's old Marine Corps buddy in the Korean War. Jack starts going to Kevin's tryouts and talks with the coach, but when Kevin sees his name crossed off the cut list, he's relieved that he wasn't receiving favoritism after all. He hits one out of the park, pretending like he's Bobby Thomson of the New York Giants baseball team in the National League pennant game of 1951.
 Guest-starring: Harrison Page as Coach Ted Baker.
 When Kevin asks his beloved algebra teacher Mr. Collins how he is doing overall in math, he doesn't get the response he needed to hear back. Instead, Mr. Collins gives Kevin private tutoring to raise his grades of C's on quizzes into A's on tests. Mr. Collins then suddenly canceled a scheduled session several days before the mid-term exam. He also announced he'd be off the next few days off but would be back to give the exam or leave it at the end of the week, leaving Kevin to fend for himself. Kevin thought Mr. Collins was helping him because he believed in him, and feels betrayed. On the day of the exam, Collins does show up with the exam that Friday, so Kevin decides to get a "respectable F" and botch the answers on purpose, much to Mr. Collins' dismay. The following Monday, Kevin regrets what he's done, and goes to Mr. Collins to apologize, only for Mr. Diperna (Raye Birk) to inform Kevin that Mr. Collins died over the weekend from heart failure. It seemed the teacher knew his end was very near (he likely knew this for some time) and at home that weekend he "misplaced" his test before passing away. Mr. Diperna asks Kevin to stay after school, but only to do a fresh test, which Kevin applies himself to. It seems that Arthur Collins believed in Kevin Arnold after all, and Kevin hands it into Mr. Diperna confident that he scored an A.
 Recurring guests: Raye Birk as Mr. Diperna; Steven Gilborn in his final appearance as Mr. Collins.
 Lisa Berlini has made up a list of categories she thinks is the definitive rating of eighth grade boys--called the "Lisa Berlini Poll." Kevin is chosen for "best eyes," while Paul's self-esteem falls when he is named the "brainiest." The boys then decide to retaliate by making their own poll about the eighth grade girls; but when Paul makes the unlikely choice of Kevin's mom for "best smile," Kevin is embarrassed, especially when his friends all agree. Paul then develops a crush on Norma when she says he looks "manly" with glasses, but she handles it well. Paul and Norma then go to a chamber music concert together and when he gives her a rose, she lets him down easy saying he needs to find girls his age, but it should be easy considering how gentlemanly he was to her.
 Recurring guest: Sean Baca as Craig Hobson.
 Absent: Danica McKellar as Winnie Cooper.
 In another "Jack vs. Karen" episode, Karen's eighteenth birthday is approaching, and tension arises with Jack when she tells him that she wants to enroll in a liberal college. When he declines her decision about her future, she suggests taking a year off to go backpacking in Europe. In the end, Jack realizes that his little girl isn't so little anymore. Karen's leaving and won't be back next year, but Jack sends her off with one last gift--his military "kit bag" from the Marines, so she can use it for college or if she goes some place. Karen then blows out her birthday cake candles, makes a wish, and goes out for the night, with her father leaving the porch light on when she returns.