Around 3:45 a.m., officers went to the Markham Avenue area of the city on a report of the vandalism.
Responding officers found two teenagers, ages 14 and 15, and a witness identified them as the suspects, police said.
The two juveniles, both Vacaville residents, allegedly admitted to slashing tires in surrounding neighborhoods and officers found at least 38 vehicles with slashed tires and one vehicle with scratches to the paint, according to police.
The suspects were booked into Solano County Juvenile Hall on charges of felony vandalism and conspiracy, police said.
Anyone with information regarding the crime is asked to call the Vacaville Police Department at (707) 449-5200.