It is the month of Ramadan. Muslims will be fasting during the day, and devoting most of early evening to prayer and introspection. What better time to reflect on Islamic fashion? Most of you probably think that religious people are not into fashion. Or that a person into fashion cannot be truly religious. Well, think again.

Islamic fashion is a mega-global business going out of its way to forge explicit links between the two. The field is led by Turkey, Indonesia and Pakistan, where proliferating companies produce, target and respond to a growing number of fashion-conscious women. At last, Muslim women, from Timbuktu to Tyneside, can be covered and fashionable, modest and beautiful.

The current bumper issue of Fashion Theory is devoted to "Muslim fashions". "Wherever they are in the world," say the editors, Annelies Moors and Emma Tarlo, "Muslim women are engaged with fashion, whether through challenging the idea of fashion, adopting and adapting local and global fashions, or by participating in the development of new trends." Abandon any suggestions that bearded mullahs dictate or define the styles of dress worn by Muslim women, or that religious prescription is incompatible with fashion. Rejoice in the emergence of a thoroughly modest and modern (if, in some cases, fully veiled) Islamic catwalk.

Even in austere and ultraconservative Saudi Arabia the demand for fashion thrives. Saudi women have to cover themselves from head to toe in the state-sanctioned abaya (an all-enveloping black cloak), but underneath they hide the hottest couture from Paris and Milan. In Yemen and south India, the same abaya is transformed into a sophisticated, cosmopolitan dress - the latest Islamic haute couture.

Designers in Egypt and Iran look to India, Lebanon and Morocco for aesthetic stimulation. Malians look to Dakar and Abidjan. Indonesians and Malaysians turn to Pakistan. Often, traditional styles are reinvented, as in Indonesia, where courtly styles of dress are in vogue, and in Egypt and Iran, where older, rural styles have been adapted to modern times.

In Britain, women borrow freely from all over the Muslim world. However, their main source of inspiration, if Fashion Theory is to be believed, is the "sartorial biography" of our own Shazia Mirza. She has become an icon of Islamic fashion thanks to a style that combines fashion, religion, politics and aesthetics to signal a new Islamic cosmopolitanism.

Yet we ought to be careful when talking about Islamic fashion. The same items of clothing can be described using different terms in different parts of the Muslim world, while the same term may be used for very different items of dress. In Britain and America, a hijab is a boring headscarf. The same scarf is called the jilbab in Indonesia. In the Middle East, however, the jilbab is a full-length coat, while in Yemen the term balto is used for the same garment. A chador in Iran and Pakistan is a large piece of cloth that is used to cover the head and the body, but in Indonesia, the chador includes a face-veil. The term shalwar kameez is used for a long tunic and loose pants in Pakistan and India. In south India, that combination is called the churidar. In Pakistan and north India, however, a churidar refers to tight drawstring trousers.

Islamic fashion, say Moors and Tarlo, is not simply about slotting Muslims into the global scene. It's all about change. Muslim women are transforming themselves through fashion. And Islamic dress styles could lead to changes in our perception of fashion itself.

I look forward to it. Meanwhile, a fashionable, happy Ramadan to my Muslim readers - and my non-Muslim readers, too.