Most military forces have developed several different uniform types, including combat dress, working dress, service or ordinary duty uniforms and (to a very limited extent) ceremonial full dress.
Today, all armies wear some form of camouflage uniforms for training and combat duty purposes. Armies facing service in different theatres may need several different camouflage uniforms.
Traditional coloured uniforms have long since given way to clothing more suited for actual combat in modern conditions. Bright colours are now usually reserved for wear by units having ceremonial functions, some bands and officers attending formal occasions. Elite units normally contrive to having some distinctive features. The United States Marine Corps are well known for their traditional midnight blue tunics and sky blue trousers (trimmed in red for NCO and above). These "dress blues" are worn for formal occasions such as the Marine Corps Birthday Ball in November. The British Household Cavalry and Foot Guards wear uniforms largely unchanged from 1914 for "public duties" i.e. ceremonial.

The military of many countries have adopted the economical expedient of smartening up combat uniforms for parade by adding medals, neck scarves and coloured berets to the terrain coloured camouflage uniforms intended for combat. As an interesting example of the combining of old and new features of uniform the French Spahis and the Spanish Regulares still wear the flowing cloaks, fezzes, turbans and sashes of the North African colonial regiments from which they are descended with modern khaki or camouflage clothing, on appropriate occasions.
The battle dress of the French Armed Forces is the FÉLIN system combined with SPECTRA helmets. France has adopted a light beige dress uniform which is worn with coloured kepis, sashes, fringed epaulettes, fourragères and other traditional items on appropriate occasions. As an alternative parade dress, camouflage uniforms can be worn with the dress items noted above. The legionnaires of the Foreign Legion wear white kepis, blue sashes and green and red epaulettes as dress uniform, while the sappers wear the basic legionnaire uniform but with leather aprons and gloves. Troupes de marine wear blue and red kepis and yellow epaulettes. The Chasseurs Alpins wear a large beret, known as the "tarte" (the pie), and mountain outfits. The single remaining regiment of Spahis retains the white cloak and red sash of the days when this corps consisted of Algerian and Moroccan cavalry.

Sailors of the French Navy and Fusiliers marins wear a dress uniform dating from the 19th century with a distinctive red pompon on the round cap.

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One purpose of military uniforms is to clearly distinguish combatants who are protected by the laws of war from other persons carrying weapons, who do not always enjoy such protection.

Another purpose in historical times was to make it difficult for deserters to avoid detection; military uniforms were so distinctive with many metal buttons and unique colours that they could not be modified into unrecognisable clothing. If the commander raised and equipped the troops out of his own pocket, the appearance of the soldiers was also designed to impress his superiors.

Attractive or distinctive uniforms could make a military career desirable to young men or women (the "peacock" factor). As late as 1914 the British Army found that regiments with particularly striking off-duty or parade uniforms found it easier to attract recruits. Thus the four Rifle regiments in their sombre dark green had a higher public profile than the great mass of line infantry in scarlet.
During the Boxer Rebellion, the Muslim Gansu Braves under General Dong Fuxiang used traditional Chinese clothing instead of western-style uniforms, reflecting the opposition of the movement to foreign influences.
The patched jibba, a garment traditionally worn by followers of Sufi religious orders, was adopted as military dress in the 1880s by the Sudanese anṣār (Arabic: أنصار) (followers of the religious leader Muhammad Ahmad al-Mahdi). The Anṣār rebelled against the Turkish Ottoman rule of Sudan, due, among other reasons, to the lax religious standards of the occupation. The jibba was a ragged, patched garment which symbolised a rejection of material wealth by its wearer and a commitment to a religious way of life. Muhammad Ahmad al-Mahdi decreed that this garment should be worn by all his soldiers in battle. The decision to adopt the religious garment as military dress, enforced unity and cohesion among his forces, and eliminated traditional visual markers differentiating potentially fractious tribes. During the years of conflict between Mahdist and Anglo-Egyptian forces at the end of the 19th century, the Mahdist military jibba became increasingly stylised and were specifically colour-coded to denote the rank and military division of the wearer.
Throughout the 18th and 19th centuries, the typical colour scheme included bright and highly contrasting colour arrangements which made it easier to distinguish units in battle. Coloured uniforms were useful in enabling commanders to spot troop locations on battlefields that were often completely obscured by smoke from the black gunpowder used in both muskets and cannons. Large flags were another aid to co-ordination and location for commanders.

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• Aiguillette
• Badges
• Bearskin
• Beret
• Brassard
• Busby
• Buttons
• Coatee
• Czapka
• Epaulette
• Fez
• Fourragère
• Garrison cap
• Glengarry
• gorget
• gymnasterka
• Hackle
• Kepi
• Medal
• Peaked cap
• Pickelhaube
• Pith helmet
• Red coat
• Ribbon bar
• Rogatywka
• Sailor cap
• Sam Browne belt
• Sash
• Shako
• Stable belt
• Tunic
• Ushanka
• Sajkaca