The Distinguished Service Order is a military decoration of the United Kingdom, and formerly other Commonwealth countries, awarded for meritorious or distinguished service by officers of the armed forces during wartime, typically in actual combat.

It was instituted 6 September(?) 1886 by Queen Victoria, the Royal Warrant being published on 9 November. It usually goes to officers ranked Major or higher, but is sometimes awarded to especially valorous junior officers. 8,981 DSOs were awarded during World War I, each award being announced in the London Gazette.

The order was established for rewarding individual instances of meritorious or distinguished service in war. This is a military order, until recently for officers only, and while normally given for service under fire or under conditions equivalent to service in actual combat with the enemy, it was awarded between 1914 and 1916 under circumstances which could not be regarded as under fire. After 1 January 1917, commanders in the field were instructed to recommend this award only for those serving under fire. Prior to 1943, the order could be given only to someone Mentioned in Dispatches. The order is generally given to officers in command, above the rank of Lieutenant-Colonel and awards to ranks below this are usually for a high degree of gallantry just short of deserving the Victoria Cross.

Since 1993, its award has been restricted solely for distinguished service (i.e. leadership and command by any rank), with the Conspicuous Gallantry Cross being introduced as the second highest award for gallantry.

Recepients of the order are entitled to use the post-nominal letters "DSO". A bar is added to the ribbon for holders of the DSO who received a second award.

The award is a gold cross, enamelled gold and edged in gold. In the centre, within a wreath of laurel, enamelled green, is the Imperial Crown in gold upon a red enamelled ground. On the reverse is the Royal Cypher in gold upon a red enamelled ground, within a wreath of laurel, enamelled green. A ring at the top of the medal attaches to a ring at the bottom of a gold bar, ornamented with laurel. At the top of the ribbon is a second gold bar ornamented with laurel. The red ribbon is 1.125 inches wide with narrow blue edges. The medals are issued unnamed but some recipients have had their names engraved on the reverse of the suspension bar.

The bar (for a second award) is plain gold with an Imperial Crown in the centre. The back of the bar is engraved with the year of the award. A rosette is worn on the ribbon in undress to signify the award of a bar.

See also

• British and Commonwealth orders and decorations