A modular button assembly includes a button housing that may be disposed in an opening of an enclosure of an electronic device. The modular button assembly may include an input member that forms an exterior surface of the button housing and is configured to receive inputs, for example from a user of the electronic device. The modular button assembly may further include a sensor to detect the received inputs and transmit a signal to a processor of the electronic device. The modular button assembly may be configured such that disposing the button housing in the opening of the enclosure forms a seal that prevents contaminants from entering the button housing and the enclosure.