Head-mounted display systems with power saving functionality are disclosed. The systems can include a frame configured to be supported on the head of the user. The systems can also include a head-mounted display disposed on the frame, one or more sensors, and processing electronics in communication with the display and the one or more sensors. In some implementations, the processing electronics can be configured to cause the system to reduce power of one or more components in response to at least in part on a determination that the frame is in a certain position (e.g., upside-down or on top of the head of the user). In some implementations, the processing electronics can be configured to cause the system to reduce power of one or more components in response to at least in part on a determination that the frame has been stationary for at least a threshold period of time.