TMO

TMO may refer to:


 * T-Mobile International AG, a German telecommunication company
 * The Muslim Observer, a weekly newspaper in Michigan, United States
 * Table Mountain Observatory, California
 * Tenant management organisation, an organisation set up under United Kingdom law
 * Thermo Electron, former NYSE ticker
 * Thermo Fisher Scientific, American firm which trades on the NYSE as TMO
 * Tortugas Mountain Observatory, New Mexico, USA
 * Television Match Official, a rugby official who assists the referee if uncertain to make a decision
 * Traffic Management Order, an order made by a United Kingdom local authority under the Road Traffic Regulation Act 1984
 * Trainman Operated Crossing, a type of level crossing
 * Transition-Metal Oxide (see also Surface properties of transition metal oxides)
 * Traditional Martinist Order
 * Trunked Mode Operation, see Digital mobile radio
 * TrackMania Original