An electronic device may be provided with a housing in which display structures are mounted. Additional input-output devices such as a track pad may also be mounted in the housing. These input-output devices may include components such as touch sensors and force sensors for gathering input from a user. The display structures may include a display such as a flexible organic light-emitting diode display or a liquid crystal display that can present visual information to the user. To provide the user with tactile output, an output device such as a display or track pad may be provided with electroactive polymer structures, electromagnetic actuators, and other tactile output devices. The tactile output devices may provide protrusions, indentations, selectively stiffened and softened areas, and other tactile output for a user.