Created by Insert Coin, the clothing range will include T-shirts, jackets, hoodies, leggings and polo shirts.
The items will be adorned with Saints Row-themed logos, places and brands, including Professor Genki, Steelport and the 'Saints Flow' energy drink.
An Insert Coin spokesperson said that fans can expect a lot of purple, while Volition's Jim Boone added: "Volition are thrilled that Insert Coin Clothing have added Saints-inspired clobber to their range.
"We can't wait to dub-test it to ensure the garments live up to the strain of saving the planet."
Launch dates are yet to be finalized, although Insert Coin believes the items will be ready for an early 2014 release.