Traditionally the patron Saint of armourers, artillerymen, military engineers, gunsmiths, miners and anyone else who worked with cannon and explosives. She is invoked against thunder and lightning and all accidents arising from explosions of gunpowder and is venerated by Catholics who face the danger of sudden and violent death in work.

St Barbara’s Day, December 4, is celebrated by, among others,:
- British (Royal Artillery
- RAF Armourers
- Royal Engineers)
- Australian (Royal Regiment of Australian Artillery, RAAF Armourers)
- Canadian (Explosive Ordnance Disposal Technicians (EOD)
- Canadian Air Force Armourers
- Royal Canadian Artillery
- Canadian Military Field Engineers
- Royal Canadian Navy Weapons Engineering Technicians
- New Zealand (RNZAF Armourers)
- RNZA
- RNZN Gunners Branch

Additionally, it is celebrated by Irish Defence Forces Artillery Regiments, Norwegian Armed Forces Artillery Battalion, United States Army and Marine Corps Field and Air Defence Artillery, many Marine Corps Explosive Ordnance Disposal Technicians, and other artillery formations.
The units and sub-units celebrate the day with church parades, sports days, guest nights, cocktail parties, dinners and other activities. Several mining institutions also celebrate it, such as some branches of the Australian Institute of Mining and Metallurgy.

The West Australian Mining Club celebrate St Barbara’s Day and use it to remember those people who have died working in the mining industry during the year. Although they do not celebrate her saint’s day, she is also the patron saint of US Navy and Marine Corps Aviation Ordnancemen.
In many mining families in the USA, the custom of the “Barbara branch” has been upheld. On this day cherry tree sprigs are cut and placed in a vase filled with water close to the light. After 21 days, exactly at Christmas, these branches blossom. Before the “Christmas tree” was known more than 100 years ago in the Westerwald, the Barbara sprigs were regarded as a symbol of Christmas as well as Christmas decoration. With their blossoms they symbolize the light and remind people that the spring sun, which will produce new flowers, is not far off. Barbara altars and windows can be found in almost all the churches of the mining communities.
Saint Barbara’s day or Eid il-Burbara is celebrated in Lebanon, Syria, Jordan and Palestine, Israel among Arab Christians annually on December 4, in a feast day similar to that of North American Halloween. The traditional food for the occasion is Burbara, a bowl of boiled barley, pomegranate seeds, raisins, anise and sugar. Walnuts or almonds can be added. The general belief among Lebanese Christians is that Saint Barbara disguised herself in numerous characters to elude the Romans who were persecuting her.