The characters on the iconic HBO series have matured, and they’ve got the wardrobes to prove it.

Hannah Horvath: From train wreck to grown-up

There’s a reason why Lena Dunham’s character looks like such a mess in the beginning of the series.

“We used to tailor clothes to actually make them look worse,” says costume designer Jenn Rogien of Hannah’s Urban Outfitters threads. “Now it’s kind of a natural off-the-rack thing — it’s not made to measure by any stretch of the imagination, but it’s a more natural fit.”

Rogien and makeup artist Sherry Heart worked on transforming Hannah’s style from hot mess to semifunctioning adult throughout the series. The “Girls” protagonist starts with mismatched prints, too-tight shorts and a disheveled mop, as a floundering wannabe author. She progresses to ladylike frocks from Williamsburg vintage shop Amarcord and a trim pixie haircut when she lands a gig as a substitute teacher. And — for this season — as a somewhat respected, in-demand freelance writer, Hannah nabs herself a snazzy yellow motorcycle jacket, worn with bright, funky sneakers and a wavy bob in one of the premiere’s opening scenes.

“I think the tagline, ‘Almost kind of getting it together’ from Season 2 is probably still a good description of Hannah’s style,” says Rogien. But she does say that Hannah’s appearance has gotten more mature and polished. “She’s still wearing a lemon-printed shirt — but it’s not clashing with another thing in her look!”

Shoshanna Shapiro: From girly to #girlboss

Shoshanna has gone a long way from naive college student in Season 1 to capable career woman in Season 6, and her style has kept pace with the wild changes in her life, including a move to Japan in Season 5.

“Shoshanna has probably had the biggest arc throughout the show,” says Joseph Campayno, who does actress Zosia Mamet’s makeup for the series. “Season 1 was a lot of glitter liner — there’s not even an inkling of that in Season 6.”

In six years, Shoshanna has scrapped the innocent pink velour tracksuits and peace-sign snuggies that she clung to when she first moved to New York City. She also dyed her glossy brunette mane bleach blond with pink streaks in Season 5 — something Mamet did without telling Heart.

“Thankfully, it worked for the character,” Heart says. And Shoshanna’s updated her girly wardrobe with a good dose of Tokyo street style.

Still, stylists maintain that Shosh is still Shosh. Heart has replaced the character’s fancy fascinators with more understated, but still playful, barrettes, while Rogien has kept her wardrobe pretty and pink, while adding some more fashion-forward pieces from Tokyo street brands and Century 21 to her usual mix of Bloomingdale’s and Zara.

“Shoshanna is all about the color palette,” Rogien says. “So I’m adding a lot of layers and hard lines in Tokyo and putting her in more assertive prints going into Season 6, but using pastels. It was all in effort to really move the character a lot, but have her feel like herself.”

Jessa Johansson: From glam bohemian to girl next door

Jessa, played by Jemima Kirke, hurtles into Season 1 of “Girls” like a hurricane — wielding her exotic British accent, toting her Louis Vuitton luggage and sporting a plethora of scarves, velvet and bohemian prints.

“Jessa started very over-the-top and very esoteric — with a lot of true vintage pieces that were very eye-catching,” says Rogien, who sourced many of the character’s early ensembles from Kirke’s own wardrobe as well as the now-closed West Village boutique Geminola, owned by the actress’ real-life mom. “As she moved forward, it got pared down just a little bit each season. So Season 1 was feathers, and Season 6 is a beautiful silk blouse.”

Jessa’s free-spirited patterned kimonos and boho dresses, always with platform heels, shifted to layered oversize T-shirts and grubby hoodies after the character’s divorce and descent into drugs and rehab. Now, however, Jessa’s style has settled into retro-flavored normcore — with cute basics from ASOS or Topshop — as she’s started a relationship with Hannah’s ex-boyfriend Adam and gone back to school.

“Her look matured along with her story,” says Rogien, citing a pair of corduroy overalls worn with a ribbed green turtleneck and powder-blue clogs in Season 5. “It was very much in direct response to what was going on in her life.”

Marnie Michaels: From basic to Jackie O

Though she may outwardly look the most put-together, with her shiny hair and her expertly applied mascara, Marnie — played by Allison Williams — is perhaps the most lost of the “Girls.”

“She’s trying on all these personas and costumes throughout the show,” says Rogien. See: Season 1’s business-appropriate Ann Taylor sheaths or the insane plastic dress she wears in Season 2 when trying to impress a hot-shot artist — a frock that Rogien made herself.

And then there were Season 4’s long dresses, crystal pendants and leather jackets, a uniform Marnie adopts when she decides to become a singer-songwriter. “Her look was always the slightly too-perfect thing that you would expect exactly for that scenario.”

Yet Marnie has slowly been loosening up her style, even donning sweats for several dark episodes in Season 5. “She’s settled into an easier place by Season 6,” says Rogien, citing the convertible look she sports in Episode 2, with a simple blouse, cigarette jeans and bold printed scarf tied around her hair. “It’s practical, because she’s in a convertible but it’s also, ‘OK, she’s having her Jackie O moment.’

“She’s Marnie, so she’ll always be trying a little too hard.”