The high-end chain has locations across the country and the nearby suburbs, but the 1723 N. Damen Ave. spot is its first Chicago store.
The shop replaces Stitch, an accessories and furniture boutique that left its 16-year home and recently reopened down the block at 1937 N. Damen Ave.
Stitch owner Pamela Hewett had said the move was prompted by rising rent costs in what's become a fashionable, pricey part of town.
Near Peek are shops such as Marc by Marc Jacobs, Lush and Club Monaco.
At Peek, kids' graphic T-shirts start at $28, denim starts at $39.50 and most dresses start at $48.
Peek, which has been around since 2006, designs and sells clothes, accessories, toys and shoes for kids up to age 12. The company also has shops in suburban Northbrook Court as well as Oakbrook Center.
Part of the company's mission is to create clothes with positive messages, Peek co-founder Tina Canales said.
"We never speak down to kids in anything we do," Canales said during a pre-opening reception Wednesday.
T-shirts sold at the store feature quotes from the novel "Siddhartha," others urge girls to "Be Brave" and "Consider Everything an Experiment."
Online, there's a boys T-shirt with the saying, "Respect Your Mother."
Canales said the company spent quite a bit of time exploring the city before picking out the Damen Avenue spot, saying they liked "the creativeness and authenticity" of Bucktown.
"We loved the vibe of the street," Canales said of the location choice.
As part of its Bucktown unveiling, Peek will give away a limited number of city-themed, "Look What the Wind Blew In" tote bags. They also have "Windy City" and "I Love Chicago" T-shirts special to the Damen Avenue store.
But a glance at some of the other items in the store, such as T-shirts with the phrases "Dude" and "Stoked," show Peek hasn't left its California roots too far behind.
For more neighborhood news, listen to DNAinfo Radio here: