In military institutions

A close-cropped or completely shaven haircut is common in military organizations. In field environments, soldiers are susceptible to infestation of lice, ticks, and fleas. Also, due to hectic operations schedules, time allowed for personal hygiene and grooming is highly curtailed or even absent. In addition short hair is also more difficult for an enemy to grab hold of in hand to hand combat.

The practice serves to cultivate a group oriented environment through the process of removing exterior signs of individuality. In many militaries, head-shaving is mandatory for males upon induction training. However, even after the initial recruitment phase, when head-shaving is no longer required, many soldiers maintain a completely or partially shaven hairstyle (such as a "high and tight", "flattop" or "buzz cut") for personal convenience and an exterior symbol of military solidarity. Head-shaving is not required of females in military service, although they must have their hair cut or tied to regulation length.

Many military organizations also require males to maintain clean-shaven faces allegedly because facial hair can prevent an air-tight seal between the face and breathing or safety equipment, such as a pilot's oxygen mask, a diver's mask, or a soldier's gas mask. However, the concerns of personal hygiene may also apply as above.

Alternatively, Foreign Legion Sappers have traditionally worn beards as a sign of their rank and experience, similarly the Imperial Guard of the Grande Armee were allowed to grow beards as a sign of their prized position. European armies before (and to some extent during) the Napoleonic wars allowed soldiers to grow and lacquer pigtails, sometimes held in place by bone combs or regimental colour ribbons or bows. In the pre-Napoleonic era, the wearing of wigs, even within the ranks was commonplace, though impractical in such places as India and the Americas. Selous Scouts, once through training and induction, were expressly forbidden from cutting their hair in any way that might indicate that they were soldiers, allowing them to engage in anti-insurgency warfare amongst the rural population of Rhodesia (now Zimbabwe). Tolerance of Sikh religious beliefs with regards to hair and beards has for some time been commonplace in most armies of former British colonies.

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