The brand's Sport line grossed between $200 and $250 million in annual sales from $0 two years ago, according to a recent report by Morgan Stanley.
Analysts say the brand could eventually grow to $1 billion.
Victoria's Secret plans to add the Sport line to 150 more stores this spring.
"We're very excited and very pleased with our sport business, especially in our bra category," CEO Sharen Jester Turney told investors. "That's where we've been putting a lot of our emphasis and seeing tremendous growth."
Victoria's Secret controls 35% of the US lingerie market and has millions of customers. Lululemon, which was founded more than two decades ago, sold $1.6 billion in 2014.
Price points on the Victoria's Secret Sport line are similar to Lululemon. Bras are priced from $50 to $60, while leggings cost between $55 and $70.
The athletic apparel industry is soaring.
Women in their 20s and 30s are largely driving the "athleisure trend," in which customers buy leggings with the intent of wearing them to the gym, errands, and brunch.
Nike is expanding its womens' line, which it says could add $2 billion in additional sales by 2017.
Dick's Sporting Goods is launching a new line, Calia, with country singer Carrie Underwood.
Under Armour is also offering more products to women.
Lululemon has always gone after this demographic.
The ideal customer at Lululemon is "a 32-year-old professional single woman named Ocean who makes $100,000 a year."
Ocean is also "engaged, has her own condo, is traveling, fashionable, has an hour and a half to work out a day," Founder Chip Wilson told NYT.