An electronic device may be provided with a housing, electrical components mounted in the housing, and optical components. A display may be mounted to the housing and may have an array of pixels overlapped by a transparent member serving as a display cover layer. Transparent members in openings in the housing may form optical component widows. A housing member or a transparent member serving as a display cover layer or optical component window may be provided with a protective coating. The protective coating may be formed on an outer surface of the housing member or transparent member. The protective coating may have a polymer binder with embedded particles. The embedded particles may be hard particles that provide the protective coating with enhanced scratch resistance. The protective coating may help enhance fracture resistance in a display cover layer or other coated member.