In the Agent Carter episode "The Lady in the Lake", Agent Jack Thompson feels very intimidated by the way the men now look up to Peggy, hence why he sends her on a case all the way across the country in LA.
Faith envies Buffy for being the "main" slayer, having friends, family, love, acceptance, etc. So she envies Buffy's life in general — right until she has to lead the charge herself.
In both Buffy the Vampire Slayer and its spin-off Angel, Angel has been shown quite frequently — despite having left Buffy for her sake — to openly display jealousy toward Buffy's love interests or suitors, especially to Riley and Spike. This is likewise the case with Spike. The episode "The Girl In Question" has them try to find her when they find out she was dating their former rival, their excuse being they were worried about her.
In the Castle episode "Eye of the Beholder", Castle and Detective Beckett are joined on their investigation by Serena Kaye, a classy, attractive insurance investigator who is clearly attracted to Castle and whom Castle begins to find intriguing in return. Not entirely surprisingly, Beckett spends most of the episode seething with badly-concealed jealousy about this.
In general, Beckett seems prone to struggling with her inner-teenager-with-a-case-of-this whenever other women attract Castle's attention. Castle, of course, returns the favour whenever other men take an interest in Beckett.
In episodes since the characters have gotten married, however, this seems to be more Played for Laughs than anything on the occasions when it happens.
Sarah Walker puts her green-tinted contacts on whenever another female takes interest in the title character. In early seasons this is played for drama, as it often betrays the feelings she isn't supposed to have in a relationship that is supposed to be a mere spy cover. In later seasons, when they become a couple for real, these instances adopt a much more comedic angle, as Sarah is very good at driving away unwanted attention from her boyfriend. Once, when Chuck unthinkingly compliments another woman's looks, she shuts him up with a Death Glare.
Chuck himself is a bit better at this when Sarah gets other suitors, as he often (mistakenly) accepts that the other guy is a better match for her. The exception is when his former-friend-turned-nemesis (and Sarah's ex) Bryce Larkin is around, then he tends to get a little pouty.
More generally, Pierce frequently falls victim to this, being older and somewhat out of touch with the younger members of the study group. He is often left out, which leads him to become more of a jerk, which leads to him being left out even more.
In Desperate Housewives episode "Back in Business", Mary Alice's ending narration focuses on the various types of envy, stating that if you look carefully at the people near you, you may spot a green-eyed monster.
Doctor Who: In "The Pandorica Opens", Rory has a brief moment of this when he discovers Amy's gotten a blanket from one of the Roman soldiers, wanting to know which one. Of course, Amy doesn't remember who he is yet, since he got retgoned a few episodes back.
In "Made You Look" Rue gets very jealous when her best friend/crush Jules talks about her new male crush. It doesn't help that Jules enlists Rue to take pictures of her in her underwear to send to "Tyler" and asks Rue if she'd want to have sex with her if she saw those pictures.
In "Shook One: Part II", Lexi does not look too thrilled when Gia tells her that she thinks Rue is in love with Jules.
One of the longest running jokes in Everybody Loves Raymond is how much Robert envies his brother, Raymond. In his rants, he would talk about how "Everybody loves Raymond", how his mother favors Ray over him, how successful Ray is compared to him, and how he has a better life than him (at least in his eyes). It gets to the point that whenever Ray fails at something or doesn't get what he wants, Robert finds joy in this and openly mocks him for his shortcomings.
While playing a conceited version of himself in Extras, Orlando Bloom seethes with jealousy over Johnny Depp:
Farscape had an episode actually called "Green-Eyed Monster", in which Crais' jealousy of Crichton (and vice-versa) nearly led to Crichton's death. It also led to John telling Aeryn about his feelings, again. To be fair, the near death was courtesy of Talyn, not Crais. He actually had him Thrown Out the Airlock.
Oh come on, Talyn gets all his ideas and feelings from Crais, pretty much. He's just a very powerful baby who wanted his Mummy and Daddy to stay together - though, admittedly, the fake sex tape of Crais and Aeryn isn't something most toddlers would come up with.
Chandler experiences quite a bit of jealousy toward Richard, the ex-boyfriend of his girlfriend Monica, as he believes that Richard is still the love of Monica's life and Richard is sophisticated, mature, an eye doctor, and is able to grow a moustache. After they're married, Monica points out how silly this is given she chose him over Richard several times. As an Insecure Love Interest, he has trouble acknowledging this. It's also worth remembering that all his previous girlfriends cheated on him, so his fears aren't exactly groundless.
Rachel and Phoebe are also this towards Monica and Chandler relationship, as they're depressed about not having anyone themselves. Lampshaded in Season 6 when Chandler's planning to propose and they say they're only 2% jealous...then 10%...then 20%...
Ross towards Paolo. Actually, Ross is this repeatedly. When they begin dating, he is extremely jealous of Rachel's colleague Mark, despite the fact that Rachel shows no romantic interest in him. He is also jealous of Emily's burgeoning friendship with Susan (Carol's lesbian lover), believing she will steal Emily from him. Monica points out that his divorce from Carol must have really done a number on Ross since in high school, Ross was not a jealous person despite the fact that ALL of his girlfriends were cheating on him.
Shae isn't happy to hear her love interest Tyrion was once a client of Ros or that he (like all men) finds his wife Sansa Stark attractive, despite being genuinely protective of her. This paranoia never really leaves, even when it becomes clear Tyrion did not consummate their marriage. Sansa is young, pretty, and (as far as King's Landing knows) heir to Winterfell. She's everything a low-born prostitute fears she cannot compete with in the long run.
Jorah Mormont bristles whenever another person gets close to Daenerys. He dislikes all the men who try to approach her romantically.
In Season 1, it's hinted that he's jealous of Daenerys's husband, Khal Drogo.
In Season 2, it's clear that he feels uncomfortable when Xaro Xhoan Daxos is near Daenerys. It just worsens when he learns about Xaro's marriage proposal.
Although not in a romantical sense, he is jealous of Ser Barristan Selmy.
Of particular note, in Season 3, he sees the mutual attraction between Daenerys and Daario Naharis, which he doesn't approve of at all. In Season 4, he becomes deeply hurt when he sees the half-dressed Daario leaving Daenerys' chambers in the morning. According to the Word of God, 'he is both incredibly jealous and a bit angry with Daenerys for falling for a man he considers so unworthy of her.'
As of Season 7, the list of rivals just doesn't end when, as soon as he is reunited with Daenerys and returns to her service, he catches a glimpse of the increasing attraction between her and Jon Snow, who is of similar age to Daenerys.
Jon reveals in "Two Swords" that he always felt his half-brother Robb was more skilled than him at most things but he could never bring himself to hate him, as Jon loved him as his brother. Sam, in turn, confesses he feels this same way about Jon, who he loves as his best friend.
When Ramsay's floozy Myranda gets jealous of another girl, he helps her hunt and kill the offending girl with his hounds and bows. Later, she's very upset when she learns that Ramsay will be marrying Sansa instead of her. When Ramsay makes it clear that he'll kill her if she makes too much of a deal about it, Myranda reintroduces Sansa to Theon so Sansa will know just what kind of person her fiancee is.
Cersei becomes a full-fledged Clingy Jealous Girl when she confronts Brienne about her Fire Forged Friendship with her brother Jaime at Joffrey and Margaery's wedding. Cersei also hates Margaery because she gains influence after marrying Cersei's sons, while Cersei's power wanes, and also because the Tyrell Queen is far more popular in King's Landing than Cersei is and ever will be.
Even though Jaime is fully aware that Tywin had arranged the forced betrothal between Cersei and Loras, and that the latter is a gay man, he is very jealous that Loras will marry Cersei while he himself cannot. Jaime threatens Loras' life over this issue when they meet at the Purple Wedding (although it backfires spectacularly).
Viserys is quite jealous of his sister when he realizes that the entire Dothraki tribe loves and respects her.
Played for laughs in Healer when Jung Hoo is just barely starting to come to terms with the fact that he may have romantic feelings for Young Shin her first crush buys the newspaper where she works and becomes their boss. Since she already told him she had a crush on the man he then spends several episodes going out of his way to get in between them while not dropping the persona of Bong Soo the incompetent coward.
An episode of Hercules: The Legendary Journeys had Cupid turn into a literal green-eyed monster when the woman he was in love with fell in love with Hercules (who reciprocated due to being struck with one of Cupid's arrows).
In House of Anubis, all the girls do this at one point or another, except for KT and Willow.
Amber was very jealous over Mara and Mick during the time Mara was running for class representative, to where she ran against her former best friend and turned into a slight Alpha Bitch in order to both win Mick back and intimidate Mara. However, she soon got over this and encouraged Mara to get back with Mick after their breakup.
Patricia has a tendency to be possessive and insecure about her relationships in general, getting jealous when Fabian was spending more time with Nina (who Patricia was bullying at this time in the show). She got much more jealous over Eddie, when he spent time with people like Mara, KT or Sophia, as it was all she could really think about a lot of the time.
Nina was pretty possessive over Fabian, to where she was angry when he merely spent a little time talking to Joy. This caused her to get very temperamental and snappy with him, while he was doing his best to keep both girls happy.
Joy herself was pretty bad, taking her jealousy over Fabian and Nina to such extremes as to write a toxic article on Nina and publish it under Mara's blogging alias, Jack Jackal. Even Patricia, her best friend, found this disgusting. Joy eventually got over this and stepped down, agreeing to just be friends with him.
Finally, Mara got nasty during the end of season 3, when she bullied Joy over falling for Jerome. She had meant to just have her friend pretend to like him as revenge for him cheating on her with Willow, but instead the two of them actually fell for each other. Mara revealed she was jealous soon after, calling Jerome her boyfriend and getting mad at Joy for liking him. Eventually they reconciled, and like the other cases, she helped Jerome and Joy get back together.
iCarly: Freddie suffers this in iLike Jake and iDate A Bad Boy. Carly also gets this like whoa during the recut version of iSaved Your Life. When another girl comes up to Freddie and offers him weekend sex with her whilst her parents and brothers are away, Carly grabs Freddie by the shoulder, embraces him and starts kissing him so the girl will take the hint that Freddie is taken, much to his surprise (and approval).
On I Dream of Jeannie, this was the entire motivation of Jeannie's lookalike sister, jealously over everything she had, especially Major Nelson. It was not a coincidence that her outfit was a green version of Jeannie's pink one.
In The Kicks, it's implied that Mirabelle's initial hostility towards Devin is because she's jealous of Devin's talent. Though Devin later admits she's a little jealous of Mirabelle too. They both get over it.
On Leverage, Parker is this during the episode "The Double Blind Job" with regard to Hardison being friendly with the client. She later breaks a beer bottle as she is watching them talk.
M*A*S*H has Margaret, who is jealous of Frank's wife. When she finds out Frank bought a set of expensive pearls for his wife and a second, cheaper set for her, Margaret devises a plan to get Frank to swap out the cheaper ones so she will have the more expensive necklace and Frank's wife will get the cheaper set.
The tables get turned when Margaret marries Donald Penobscot. Frank's own jealousy causes him to kind of lose his marbles and he ends up sent back to America on a Section 8.
Prince Arthur a couple of times on Merlin. He responds to the sight of Lancelot and Guinevere holding hands by throwing a Big Sulk (and this is before he and Guinevere are in a relationship), and later gets riled at Gawaine for flirting with her. The fact that both knights have been reinstated at Camelot gives you the feeling that this is heading somewhere
MythQuest: In one episode, Cleo visits a Swahili fairy tale. The brother of the fairy tale's protagonist refuses to let her have any success, always claiming that whatever she earns belongs to him, despite how much wealth he already has.
On Once Upon a Time, Zelena, the Wicked Witch of the West, physically turns green when she allows her envy get the better of her. Once she gets over the fact that Rumpelstiltskin chose Regina over her, she returns to normal. Then she gets envious when Dorothy Gale turns up in Oz and is prophesied to be The Chosen One, so she turns green again.
On The Paradise, Katherine Glendenning is jealous because Moray, her boyfriend and later fiancé can't seem to forget his dead wife. She considers this this the reason they have not married yet. She tries to remove her painted portrait from his office without permission. Once Denise Lovett, the new shopgirl, catches the eye of Moray, Katherine changes targets. Her envy is greater because Denise was able to make John Moray forget Mrs. Moray while she couldn't. Katherine does not allow Moray to break up the engagement. She waits until the day of the wedding to do it herself. She exiles Moray and thanks to her rich banker dad, now she owns The Paradise, Moray's life's work.
In Robin Hood, Guy of Gisborne envied Robin his popularity and status as a national hero, and the love of Marian.
In the third season, Kate envied Isabella and Guy because of Robin's continual obsession with all things Gisborne-related.
During Selfie, this trope pops up a little between Henry and Eliza-despite not being in a relationship, the two have feelings for each other and this tends to come out when they talk about other people. Henry says Eliza's sex buddy Freddy is a tool, and Eliza gets a way bigger dose of this trope when Henry dates Julia, insulting her height, and trying to come between the couple so as to not lose out on spending time with Henry.
Played for Laughs in order to alleviate the high levels of tension in an otherwise rather grim and humourless episode of Sherlock (which is known - and loved - for its dry wit): John spends the entirety of A Scandal in Belgravia reveling in barely-concealed jealousy over how much attention Sherlock awards Irene, to the point where his Girl of the Week breaks up with him for being a better boyfriend to Sherlock than he is to her. John becomes completely incensed after the first time Irene fakes her own death, threatening her in an attempt to convince her to tell Sherlock that she's still alive. This doesn't stop him from feeling sorry about her apparent death at the end of the episode. Sherlock himself suffers from the Green-Eyed Monster whenever something other than the case they're working on distracts John.
One of the Monsters of the Week on Sleepy Hollow was Ichabod's ex-betrothed, a woman who became an evil spirit after her death and targeted women that she considered romantic rivals.
Lex: You were always one step ahead of me. Clark: It wasn't a competition. Lex: Of course it wasn't; you're simply better than the rest of us. Clark: And that always killed you, didn't it? Lex: No. What killed me was that you didn't evenwantit. You rejected it. If I had your destiny, I would have embraced it.
On Star Trek: Voyager, Neelix refers to jealousy as "that green-eyed pus-hog." Typically, he does so in reference to his own jealousy of what he thinks is Tom Paris trying to get too close to Kes. This leads to a food fight in the mess hall before they get sent on an away mission, during which they finally patch things up.
This comes up periodically in Supernatural; people who don't know the boys see that they're handsome, tall, competent, charming, good liars, etc., and conclude they have it easy. As the stars of one of the most depressing shows on television, this is emphatically not true.
The loser behind the problem in the wishing well episode says something to the effect of them having it easy with their great looks and cool car, and they assure him in deadpan that they are absolutely miserable. This is a little surreal, in that it's true, but they say it like they're remarking on the weather. On the other hand, Sam lies to the asthmatic warlock kid in 'Swap Meat' that he'd love to have his life without the demon bounty hunters and blood addiction problems and responsibility for the Apocalypse and all that. Actually, he'll take all that rather than be that kid with the collegiate future locked in stone by his asshole family, and a no-good body. Probably the most significant factor being that by Season 5 Sam has long since grown uncomfortable with restrictions on his ability to kill the fuck out of his problems, and is not actually fit to live in society anymore, even if he is wearing a white hat again.
Surgical Spirit has Sheila, who used to date a coworker, got engaged to him but they then split up. Both of them start dating other people, but when the coworker's new girlfriend joins the hospital as a nurse, Sheila isn't particularly kind to her for the first few days. She gets better, though.