Under the kingdom’s strict dress code for women, Saudi females are required to wear a headscarf and loose, black robes in public. Most women in Saudi Arabia cover their hair and face with a veil known as the niqab. But covering one’s head is not required for foreigners, and some Western women choose to forego the headscarf while in Saudi Arabia.

As a delegation of dozens of Saudi officials — all men — greeted the Obamas in Riyadh, some shook hands with Mrs. Obama. Others avoided a handshake but acknowledged the first lady with a nod as they passed by.