DCO

DCO may refer to: Diploma in Community Ophthalmology

Astronomy

 * Dark compact object, a dark compact star

Technology

 * Device configuration overlay, of a computer hard disk drive
 * Digitally controlled oscillator, in electronics
 * Siemens DCO, a telephone switch
 * Drift City Online, a game
 * Domain controller, on Microsoft Servers
 * Developer Certificate of Origin, used in open source software projects to verify individual contributions

Other

 * Deep Carbon Observatory
 * Development Consent Order, the means of obtaining permission for nationally significant projects in England and Wales
 * Digital Cooperation Organization, an international organization
 * Dimension Century Orguss, anime series
 * Direct commission officer, a military rank
 * Disney Channel Original (disambiguation)
 * District coordination officer, a civil service position in Pakistan
 * The British Columbia Regiment (Duke of Connaught's Own), a regiment of the Canadian Forces
 * Duke of Cambridge's Own, aka Middlesex Regiment
 * Dynamic Creative Optimization, a term used in programmatic marketing
 * D.Co., an abbreviation used for the United States District Court for the District of Colorado
 * Docket Control Order, a legal document used to confirm court deadlines.
 * Document Control Officer controls access to documents that are restricted to certain people