Military chocolate has been a part of standard United States military rations since the original D-ration bar of 1937. Today, military chocolate is issued to troops as part of basic field rations and sundry packs. Chocolate rations served two purposes: as a morale boost, and as a high-energy, pocket-sized emergency ration. Military chocolate rations are often made in special lots to military specifications for weight, size, and endurance. The majority of chocolate issued to military personnel is produced by The Hershey Company.

When provided as a morale boost or care package, military chocolate is often no different from normal store-bought bars in taste and composition. However, they are frequently packaged or molded differently. The World War II K ration issued in temperate climates sometimes included a bar of Hershey's commercial-formula sweet chocolate. But instead of being the typical flat thin bar, the K ration chocolate was a thick rectangular bar that was square at each end. (In tropical regions, the K ration used Hershey's Tropical Bar formula.)

When provided as an emergency field ration, military chocolate was very different from normal bars. Since its intended use was as an emergency food source, it was formulated so that it would not be a tempting treat that troops might consume before they needed it. Even as attempts to improve the flavor were made, the heat-resistant chocolate bars never received enthusiastic reviews. Emergency ration chocolate bars were made to be high in energy value, easy to carry, and able to withstand high temperatures. Withstanding high temperatures was critical since infantrymen would often be outdoors, sometimes in tropical or desert conditions, with the bars located close to their bodies. These conditions would cause typical chocolate bars to melt within minutes.