It is acceptable for men doing business in Saudi Arabia to wear dark-colored business suits, especially to initial meetings. A tie in a conservative pattern is best, and it's not always necessary to wear a suit jacket, especially in very hot weather. In some instances, when overall office attire is casual, it is proper etiquette for men to wear business casual attire to a meeting; this includes slacks or khaki pants with a button-down or polo shirt.
It is most appropriate for professional women to dress conservatively in Saudi Arabian offices. Women should avoid wearing sleeveless tops or shirts that show any cleavage. Shirts should cover at least the elbow, but long-sleeved shirts--even in warmer weather--are best. Skirts and dresses should fall below the calf, and pants are usually permitted in the workplace.
While foreigners who are doing business in the country can wear business suits, Saudi Arabian men usually wear thobes to the workplace. Thobes are long white robes that cover the man's entire body. Head covers, or ghoutrah, are also worn by the men, as well as egaals or black head bands. Generally, businessmen from other countries are not expected to wear these items; in many instances, it is considered insulting for foreign men to dress to much like their Saudi Arabian counterparts.
When professional women are visiting Saudi Arabia, they are expected to wear a abayya any time they are in public--including when they are at work. The clothing that women wear underneath the abayya should still be modest and conservative. The abayya is a long robe or cloak that covers all of the woman's clothing; it reaches down to her feet. Women are also expected to wear a headscarf that covers all of their hair when in any public place, even if they are not native to Saudi Arabia. In some parts of Saudi Arabia--such as the Jiddah region--some younger women wear their abayyas open to reveal their clothing underneath.
Even though the dress code for some Saudi Arabian offices may be more relaxed, it is still generally considered improper etiquette to wear jeans in a professional setting. Shorts are also not permitted for men or women, as they show too much of a person's skin in public. It is also best for professional men and women to keep their accessories minimal and modest. For the most part, wearing a watch and wedding band are sufficient.
