| OTO | Oil Taxation Office (UK) | 石油税务局（英国） |
| OTO | One Time Only | 仅限一次 |
| OTO | Orthotolidine | 邻甲苯胺 |
| OTO | Outflow Tract Obstruction | 流出道阻塞 |
| OTO | Ordo Templi Orientis (Order of Oriental Templars) | Ordo Templi Orientis（东方圣殿骑士团） |
| OTO | Online Tour Operator | 在线旅游运营商 |
| OTO | Operations Training Officer | 运营培训官 |
| OTO | Otomian Languages | 奥托米亚语言 |
| OTO | Onderzoek en Technologische Ontwikkeling (Dutch: Research and Technological Development, aka: RTD) | Onderzoek en Technologische Ontwikkeling（荷兰语：研究与技术开发，又名：RTD） |
| OTO | Of Terrestrial Origin | 地球起源 |
| OTO | Or Top Offer (classified ads) | 或最优惠（分类广告） |
| OTO | Ozarks Transportation Organization | 奥扎克斯运输组织 |
| OTO | Otology | 耳科学 |
| OTO | Ordo Templi Orientis | 东方神殿教的介绍 |
| OTO | One To One | 一对一 |
| OTO | Once- Through Oil | 直流油 |
| OTO | Overture To Orchestra | 管弦乐队序曲 |
| OTO | Operations And Training Officer | 运营和培训官 |