Historically, an armourer is a person who makes personal armour, especially plate armour.^{[citation needed]} Historically armourers were often men, but women could also undertake the occupation: for example Alice la Haubergere worked as an armourer in Cheapside in the early 1300s and in 1348 Eustachia l’Armurer was training her husband's daughter, likely in the field.

In modern terms, an armourer is a member of a military or police force who works in an armoury and maintains and repairs small arms and weapons systems, with some duties resembling those of a civilian gunsmith. The term may also be used in film and TV production for a person responsible for prop guns and other weapons; the head of this function is often called a weapons master.

There is increasing evidence that companies specializing in the manufacture of armoured vehicles or applique armour for application onto vehicles of all types (cars, boats, aircraft) are referring to themselves as armourers; such as the UK company OVIK Crossway - which describes its services as Armourers and Coach Builders. In some ways, this is a reversion back to the original meaning of the term insofar as these companies forge, adapt or integrate physical armour onto platforms in order to protect human life.

The title is also used in the sport fencing (the foil, the épée and the sabre) to refer to those who repair fencers' weaponry, safety equipment, fencing-strips, scoring machines, and reels. At sport-fencing events, the individuals responsible for checking equipment safety and maintaining the strips, reels and scoring machines during the tournament are also known as armourers.^{[citation needed]}

With the renewed interest in traditional armour and weaponry the occupation also involves working with film, stage, and historical and reenactment societies. Period costumes may require reproduction armour, swords, and related equipment. The HEMA (Historical European Martial Arts) movement has also revived a more traditional expression of armoury as a skill.

Armourers are the oldest trade in the British Army and trace their heritage back several centuries. Today they form a core role within the Corps of Royal Electrical and Mechanical Engineers (REME) and work on an extremely wide variety of weapon systems. Typically, armourers are attached to every type of front line operational unit within the British Army such as Infantry, Cavalry, Engineers, Logistics, Special Forces and specialist training teams. They can also be found in larger REME units called REME Battalions providing in-depth repair and front line support.

Armourers have the rank of Craftsman upon starting their trade training, which is the equivalent of Private and they have similar ranks of the remainder of the Army thereafter. As they increase in rank they can follow one of two streams: Artisan or Artificer. As an Artificer they must complete a strenuous Selection course and then attend an 18-month intensive engineering course where they work towards and gain an electrical and mechanical HND, upon completion they emerge as a Staff Sergeants (SSGT) and have the potential to reach Warrant Officer Class 1 (WO1) as an Artificer Sergeant Major (ASM) or even gain a Commission. Artisan Armourers who remain working at trade can also achieve Warrant Officer Class 1 (WO1) typically as a Regimental Sergeant Major (RSM) of a REME Battalion and potentially gain a Late Entry (LE) commission.

On a day-to-day basis Armourers maintain a wide variety of weapons and optical equipment, they are highly skilled in the use of hand tools and are able to maintain their equipment across the globe. They formally inspect every weapon annually/or every six months (dependent on weapon type) and also advise the end-user on all matters of equipment care. Within a modern Infantry Battalion, they are exposed to the maximum varieties of weapons and optical equipment, with only Special Forces possessing more.