• Ótr, a dwarf in Norse mythology
• Otr, the abbreviation for the orchid genus Otaara
• Otierre aka OTR, an Italian hip-hop band
• Coto 47 Airport , an airport that serves Coto 47, Costa Rica

OTR is an acronym for:

• On The Rocks, the rock band featuring British, Dutch and Brazilian members.
• Off The Record (OTR/PRESS News Agency), A Spanish newswire for media
• Off The Record (TV series), A Canadian sports talk show
• Off-the-Record Messaging, an instant messenger encryption protocol
• Old-time radio, a term describing an era of radio programmes in the first half of the 20th century
• Organisation and Technology Research (OTR plc), a European IT research company
• Over-the-Rhine, the Cincinnati neighborhood
• Over the road, A legal beagles term.
• Over the Rhine, an Ohio-based band
• Oxygen transmission rate, a measure of a barrier material's oxygen permiability
• Over The Top Rope, a group of WWE Royal Rumble fans
• On The Rag, a woman's period; flow; menstrual cycle.
• On the Run (convenience store), an international convenience store chain owned by ExxonMobil
• OnlineTVRecorder, a TV-recording service with nearly all German and some English channels (look at OnlineTVRecorder)
• Truck Driver, Over The Road Truck Driver, Truck Driver that spends a few or more days "On the road"
• Optical Transition Radiation, in Physics the radiation emitted by a charged beam at the interface between 2 mediums.
• Optical TRansponder, a term describing electronic equipment used to transmit optical signals between two locations.