A stud finder (also stud detector or stud sensor) is a handheld device used with wood buildings to locate framing studs located behind the final walling surface, usually drywall. While there are many different studfinders available, most fall into two main categories: magnetic studdetectors and electric stud finders.

Even though only commercial buildings use metal studs, magnetic stud finders, which are still available, work with wooden studs, too, by locating the metal nails used to mount the wallboard or wooden lath. A newer type of stud finder works by detecting density changes in a wall.