An electronic device such as a voice-controlled speaker device may have a housing. A speaker and other input-output components and control circuitry may be mounted within the housing. Light-emitting components may emit light that passes through a curved upper top cap portion or other housing structure. The light-emitting components may be interconnected using a flex circuit on a curved substrate or may be mounted on a planar circuit board. A subset of the light-emitting components may be rotated to improve color balance. Optical structures such as light guides, lens, microlenses, and/or a diffuser layer may be disposed over the light-emitting components to promote light mixing, to reduce hotspots, and to improve contrast on the top cap. The diffuser layer may be suspended using a support structure having baffle members to constraint the angular spread of the emitted light. Illuminated or persistently visible glyphs may be displayed in or near the top cap portion.