| Acronym | Definition |
|---|
| OTU | Operational Training Unit |
| OTU | Operational Taxonomic Unit |
| OTU | Oxygen Toxicity Unit (scuba diving) |
| OTU | Optical Transport Unit (IEEE) |
| OTU | One-Time Use (disposable) |
| OTU | Over to You |
| OTU | Oxygen Tolerance Unit |
| OTU | Office of Technology Utilization |
| OTU | Oceania Taekwondo Union |
| OTU | Optical Translator Unit (Lucent) |
| OTU | Overrating the Underrated (music website; UK) |
| OTU | Once-Through Utility (boiler type) |
| OTU | Output Terminal Unit |
| OTU | Operating Time Update |
| OTU | Outcome Tracking Unit |
| OTU | Occupational Therapy Unit |
| OTU | Organizational Taxonomic Unit |
| OTU | Old Town Underground (Michigan) |