Virgos are mature, with a stoic outlook on life. They're always there for their friends and are loyal to a fault. This very succinctly sums up Anna Kone, the other main character in the show. Since her parents are going through a divorce, she is more mature than many of her friends of the same age. In true Virgo form, Anna was there for her friend Maya when she forgot the lines in the school play, and her calm, quick-thinking ways truly helped her friend get out of a sticky situation.
Yuki is portrayed by Maya Erskine's real-life mother, Mutsuko Erskine (which, although pretty cool, is not the first time a real-life mother and daughter played a mother and daughter onscreen). She balances the discipline necessary to be a "single parent" with the love needed for a child to flourish. Like the scales which represent Libra, she tries to constantly keep things in a state of harmonious balance.
Maya's father is a traveling musician in a touring Steely Dan cover band, and his near constant absence creates an emotional vacuum which is common to Capricorns. Poor impulse control and impulsiveness are hallmarks of Capricorns, and Fred has displayed both these traits in his decision making process over the years.
Luckily for Maya, Fred manages to make it home for the big events, like her drum competition in which she forgot the music she was supposed to play and just winged it. He was proud of her regardless.
Maya's older brother teases her relentlessly, as a typical Aries would. Aries tend to be insensitive when it comes to the emotions of other people. However, he's there for her when the chips are down, helping her with schemes of revenge. Although Aries can seem insensitive to the feelings of other people, once they are on your side, they can be counted on no matter what.
Anna's mother, Kathy, is into crystals and new age therapies, but even hippie rainbows can't keep her stinging tongue from picking fights with both her ex-husband and her daughter. Scorpios act out to cover for their own emotional pain and immaturity, and Kathy fits this description to a T. She is combative, super emotional and controlling, while never really confronting her own mistakes or missteps.
Curtis would never be considered a villain, but he is a dad who is going through a bit of a mid-life crisis right in front of his daughter, Anna's, eyes. Pisces are insecure over-thinkers, and Curtis over-thought his way to a pierced ear and a convertible, often sleeping on the couch in order to avoid the wrath of his soon-to-be-ex-wife.
Geminis are known for being extroverted and clever, which Sam certainly is, often using humor as a shield. He has a grounded and relatable nature, and even feels badly after insulting Maya and Anna, showing a sensitivity and empathy typical for Geminis. Sam is a good guy who tries to do the right thing, even if that proves difficult.
Sagittarius is known as the truth-seeker of the Zodiac. This describes Gabe quite nicely, in that he is a boy struggling with his sexuality, and with who he really is inside. He is exploring his truth like only a Sagittarius can. He is honest with his emotions and his friends, dating Maya not just as a front, but because he genuinely likes her. Gabe is happy to still be a kid in many ways, content to hand draw his magazine dedicated to the wonderful world of weasels, waiting just a little while longer to grow up and face the 8th grade.
Heather is the resident popular girl on Pen15, and boy does she know it. She's vain, catty and has a big personality, just like Leos tend to have. And like other Leos, beneath all that bravado beats a heart of gold.
When Anna's parents divorce, Heather is very supportive and nurturing, having gone through a parents divorce herself. She showed her tender side to Anna when she needed it most.
People with the Zodiac sign of Taurus are known for being straight-forward and blunt. This describes Alex, the object of Anna's crushing desires, perfectly. Anna builds up the courage to ask him to slow dance with her, and he says "no" as casually and cruelly as if she had offered him a piece of candy. The look on Anna's face makes this one of the cringiest scenes in a show built on cringe-worthy scenes like Pen15. Like a typical Taurus, Alex just has no idea that people's feelings could be hurt by the things that he says.
Aquarius is a sign of popularity and quirkiness, which describes Brandt very well. He is well known by everyone and tends to blend in and fit in with several groups. Like a typical Aquarius, Brandt lacks a filter when dealing with other people, and as a result can seem brash and insensitive, when he is actually highly sensitive himself.