CTO may refer to:

• Chief technology officer, an executive officer in an organization focused on scientific and technological issues
  • Chief Technology Officer of the United States
• Certified Television Operator, an operator certified by the Society of Broadcast Engineers

• Cape Town Opera, South African opera company
• Caribbean Tourism Organization, for sustainable tourism
• Commonwealth Telecommunications Organisation, a partnership between Commonwealth and non-Commonwealth governments, business, and civil society organisations
• Cyprus Tourism Organisation, a semi-governmental organisation in Cyprus
• CTO Hospital (Turin), a major medical center in Turin, Italy

• Cancelled-to-order, a postage-stamp cancelled by the postal administration before sale to stamp-collectors
• Activated carbon filter to improve Chlorine, Taste, Odor
• Chronic total occlusion, a disease of a coronary artery of the heart
• City ticket office for an airline
• Color temperature orange, a type of color gel filter used in color correction
• Community treatment order, an implementation of mental-health law in Australia, England and most provinces in Canada
• Crude Tall Oil, a viscous yellow-black odorous liquid obtained as a by-product of the kraft process of wood pulp

• Central Treaty Organization (CenTO), a former intergovernmental military alliance