RDH

RDH may refer to:


 * Redhill MRT station, Singapore (MRT station abbreviation)
 * Redhill railway station, Surrey, England (National Rail station code)
 * Registered Dental Hygienist
 * Retinol dehydrogenase, an enzyme
 * Royal Darwin Hospital, Northern Territory, Australia
 * Reference datum height, an aviation metric
 * Radiotron Designer's Handbook, a famous book by Wireless Press