On the outside, there’s nothing special about the steel lockers that line the corridors of American schools. Inside, it’s another matter. With a helping hand from savvy retailers, junior high school girls eager to stay in step with fashion are personalyzing their lockers like never before, embracing them as blank canvases on which to express themselves. No longer are lockers just a place to stash dog-eared textbooks, a peanut butter and jelly sandwich for lunch, and maybe a pop idol’s photo. Now they can become a thing of beauty — at least in a teenager’s eyes — adorned with everything from mini chandeliers to wallpaper. “It started to emerge in the last couple of years,” Deborah Kasak, executive director of the National Forum to Accelerate Middle-Grades Reform, an education think-tank and advocacy group, said. “Middle grades is a time of personality formation so young adolescents try out things as they begin to carve out who they are and who they will become,” she said. “This might be an extension of that need.” Inei Duenas, 12, who attends North Bethesda Middle School outside Washington, has lined her locker with blue paper, then added pictures, “a whiteboard to jot down stuff I need to do and a mirror to fix my hair.” Her friend Johanna Chatelain, who is French, has equally embraced this very American trend: “I have a mirror, a carpet, a blackboard, too. Everything is in green. I really love my locker, it makes me think of a little house.” Both online and mainstream retailers have been quick to jump on the locker bandwagon in a country where, according to the National Retail Federation, families spend an average of $690 for back-to-school clothes and supplies. JoAnn Brewer and Christi Sterling, two mothers from Dallas, Texas, launched what they call a “locker fashions” supply company, Locker Lookz, that peddles its wares both online and through 1,200 retailers nationwide. Specially designed wallpaper to line the inside of a locker costs $23 and comes in a variety of shades and patterns, from pink flowers and zebra stripes to polka dots on lime and black-and-white hounds tooth. In lieu of adhesive backing, the wallpaper attaches itself with magnets, so there’s no permanent impact on the locker. It’s also cut in order to make room for a locker’s built-in locking mechanism. Dozens of accessories that go for about $10 each from Locker Lookz include rugs, curtains, baskets for storing makeup or pens and even lighting. “Our motion-sensor locker chandelier, which we introduced to the market in 2011, has been the favorite among both retailers and consumers,” Brewer said. Magna card, which specializes in magnet-backed business cards, has meanwhile established a separate line of locker products. “Many girls make a big deal out of their first locker,” said its president Paul Buckel. “These girls get so excited about their lockers that they actually have a locker decorating day to get ready for school.” On YouTube, a mother named Jenny demonstrates do-it-yourself techniques using cheap materials, in a series titled “Cute Locker Decorating Project.” One episode features her 11-year-old son looking rather bashful.