An electronic device may be provided with environmental sensors. Environmental sensors may include one or more environmental sensor components and one or more acoustic components. Acoustic components may include a speaker or a microphone. Environmental sensor components may include a temperature sensor, a pressure sensor, a humidity sensor, a gas sensor, or other sensors or combinations of sensors for sensing attributes of the environment surrounding the device. The environmental sensor may have an enclosure with an opening. The enclosure may be formed from a rigid support structure and a portion of a printed circuit. The opening may be formed in the rigid support structure or the printed circuit. The opening in the enclosure for the environmental sensor may be aligned with an opening in an outer structural member for the device. The outer structural member may be a housing structure or a cover layer for a device display.