Jealousy among cast members...

[88survivor]

While kind of the same thing as feud, but name actors on certain that were jealous of other actors on their show.

Growing Pains

Tracy Gold being jealous of Kirk Cameron's fame on the show because he was the center of attention.

Silver Spoons

Rick Schrodder being jealous of Jason Bateman's character stealing the spotlight from him when the producers finally rid his character to bring in Alfonso.

[comedyfreak]

Family Matters-Jo Marie Payton overshadowed by urkel.
Lost In Space-Guy Williams overshadowed by Smith, The Robot, and Will.
I Love Lucy-Vivian Vance hated having to look frumpy next to Lucy.

[mstewart]

Linda Lavin of Polly Holliday and Diane Ladd because their characters took the spotlight from them especially Polly in her portrayal of Flo. Watch season 4 episodes and you can see the tension between those two.

Rose Marie was jealous of Mary Tyler Moore on the Dick Van Dyke Show because Mary's character, Laura, was the breakout character of the show. Rose was suppose to be the leading actress on the show and Mary ended up being unofficially the leading actress on the show. Even though on the billing it was always last with, "and Mary Tyler Moore."

[Dean Winchester]

Family Ties - Meredith Baxter hated that Michael J. Fox became the star of the show
Laverne And Shirley - Cindy Williams eventually quit because she felt like the producers and network favored Penny Marshall

[snl 70s show fan]

its been said that topher grace was a bit miffed when ashton kutcher got bigger and bigger storylines on that 70s show

[treky]

I LOVE LUCY-Vivian Vance and William Frawley HATED each other, and HATED playing a married couple. In fact, he could be heard in his dressing room sometimes shouting things like "I'M NOT DOING THIS SCENE WITH THAT BITCH"!! She also thought he was too old to be playing her husband, and having to wear "frumpy" house dresses. Also that she had to gain whieght for the role.
Once, when she was doing "THE LUCY SHOW" and he was doing "MY 3 SONS" down the hall, during a break in the "M3S" filming, he went down to the "TLS" set and took Stanley Livingston with him. He had Stanley climb up a catwalk, and stand above her, then drop a heavy piece of metallic equipment behind her, and startle her. Then the 2 of them ran back to the M3S set, laughing and he said "That'll show that bitch"!
Later, when she heard that he had died; she was having dinner with friends. she raised her glass in a toast and said "I thought he'd never die".

But, I've also heard that they just hated each other at work, and NEVER that much; in fact; if she ever heard that he was hospitalized, or anything, she'd drop everything to be by his side-even if it meant flying halfway or all the way across the country.

[Shine]

William Shatner was jealous of the attention that Leonard Nimoy received on Star Trek. Even though Shatner got plenty of attention himself, I think that he sort of wanted it all.

[88survivor]

Was there jealousy with Julie Cobb and the producers about money issues? I seem to read from Michael Pearlman's post was that she had a disagreement over the salary issue, which is why she was replaced by a different Mrs. Pembroke.