Mentioned in Despatches (MID) is a military award for gallantry or otherwise commendable service.
In the British Armed Forces, this report is published in the London Gazette. If a subordinate officer or soldier performs a noteworthy action included in the report, he/she is said to have been "mentioned in despatches".
In the nations of the British Commonwealth, soldiers who are mentioned in despatches, whilst not awarded a medal, receive a certificate and are entitled to wear a silver or bronze (depending upon date) oak leaf on the ribbon of the campaign medal issued to soldiers who served in a campaign or conflict. From 1920 to 1994, the oak leaf was bronze, and in the Canadian Forces it still is. If no campaign medal is awarded, the oak leaf is worn on the left breast of dress uniform. The oak leaves were first issued after the end of World War I.
Soldiers can be mentioned multiple times. The British World War I Victoria Cross recipient John Vereker, later Field Marshal Viscount Gort, was mentioned in despatches nine times, as was the Canadian general Sir Arthur Currie. The Australian general H.G. Bennett was mentioned in despatches a total of eight times during the First World War, as was John Dill.
Australian service personnel are no longer eligible to be Mentioned in Despatches. Since 15 January 1991, when the Australian Honours System was established, the MID was replaced by two Australian decorations—the Commendation for Gallantry, a fourth level gallantry decoration, and the Commendation for Distinguished Service, a third level distinguished service decoration.
Mention in Dispatches is an award to recognize a mention in dispatches from a senior commander for brave or meritorious service, normally in the field. Mentions in Dispatches are among the list of awards presented by the Governor General of Canada.
Under the current Pakistani military honours system, the Imtiazi Sanad is conferred upon any member of the Pakistani armed forces who are mentioned in dispatches for an act of gallantry that does not qualify for a gallantry award. 
In 1920 the Minister of Defence of the Union of South Africa was empowered to award a multiple-leaved bronze oak leaf emblem to all servicemen and servicewomen mentioned in despatches during World War I for valuable services in action. The emblem, which was regarded as a decoration, was worn on the ribbon of the Victory Medal (Union of South Africa). Only one emblem was worn, irrespective of the number of times a recipient had been mentioned. 
The Afrikaans rendition of Mentioned in Despatches is Eervolle Vermelding in Berigte.
In 1943, the Union Defence Force confirmed the availability of the British award, the bronze oak leaf, for acts of bravery, in contact with the enemy, which fell just short of the standard required for the granting of a decoration, or for valuable services not necessarily in immediate contact with the enemy.
The Mention in Despatches (MID) was one of only four awards which could be made posthumously. The others were the Victoria Cross, the George Cross, and the King's Commendation (South Africa). The oak leaf emblem was worn on the ribbon of the War Medal, 1939-45. The MID and the King's Commendation (SA) were the only decorations that could be approved by the South African Minister of Defence without reference to the King. 
The King's Commendation (South Africa) (1939-45) was denoted by a bronze King Protea flower emblem worn on the ribbon of the Africa Service Medal, for valuable services in connection with the World War II. It could be awarded posthumously and was the equivalent of a Mention in Despatches for services rendered away from the battlefield.
In the French military, mentions in Despatches—or more precisely, mention in Orders (citation dans les ordres)—are made by senior commanders, from the position of regimental commanding officer to General-in-Chief, in the Orders they give to their unit, recognizing the gallantry of an action performed some time before. The mentions are awarded for gallantry to any member of the French military or its allies and are, depending on the degree, roughly the equivalent for U.S. Bronze Star and Silver Star or UK Military Cross and Military Medal.
Mentions made during World War I, World War II or colonial conflicts were accompanied with awards of a Croix de guerre or a Croix de la Valeur Militaire, with attachments on the ribbon depending on the mention's degree : the lowest degree is represented by a bronze star while the highest degree is represented by a bronze palm
Nowadays, a mention with award of the Croix de la valeur militaire (the Croix de guerre is no longer awarded) is rare, and most mentions are awarded with a gold Médaille de la Défense nationale and the same attachments as the Croix de guerre.
A unit can be mentioned in Despatches. Its flag is then decorated with the corresponding Croix. After two mentions, the men of the unit are entitled to wear a fourragère.
In the early U.S. Army no awards or medals were given with the exception of a Purple Heart then known as the Badge of Military Merit, though this award fell into disuse shortly after the Revolution. Being noted in dispatches or official reports was the common manner in which to recognize heroic action and gallantry of individuals and units.
On July 12, 1862, the Medal of Honor was created, thus instituting a system of awards in the U.S. Armed Forces. In the years leading up to World War I, citations for bravery, very similar to the Commonwealth practice of MID, evolved into Citation Stars, and eventually the Bronze and Silver Star Medals.
On October 3, 1863, The Adjutant and Inspector-General's Office at Richmond, Va., published General Orders No. 131 establishing The Roll of Honor. Names published were to be read at the head of every regiment at the first dress parade after its receipt and published in at least one newspaper in each State.
During World War II, the Wehrmacht sometimes mentioned individual soldiers in its daily radio report to the public. This was known as the Wehrmachtbericht and a mention in this report was held in high esteem by German soldiers. In mid 1941 mentions in Wehrmachtbericht were awarded by the soldier's name being included on the Honour Roll of the German Army. Later, after January 1944, inclusion on this list was also sometimes awarded with an honour clasp, known as the Honour Roll Clasp of the Army.