Nine men have been arrested on suspicion of conspiracy to commit sexual activity with a child.
Two addresses in Loudon Street and Walbrook Road in the Pear Tree area of Derby were raided at 22:00 BST on Friday.
Derbyshire Constabulary said there was a "significant police presence" in the area at the time of the raids.
The men, aged between 20 and 47, remain in police custody, the force said.
Six men were arrested on Friday and three more were arrested in the early hours of Saturday.
Eight are from Derby and one is from outside Derbyshire, police said.