I would like to know the ruling on a Muslim woman wearing her hair in a high bun (on top of her head), like bridal hair style for example.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

It is permissible for a Muslim woman to beautify herself as she pleases on the condition that this beautification is not an imitation of what is peculiar to a man, or a non-Muslim woman, or dissolute women. She should not show this beautification except in front of those who are permitted (Islamicly) to see her beauty. It is confirmed that Imaam Muslim reported that the wives of the Prophet used to shorten their hair (up to the level of their earlobes). So there is no harm for a woman to wear her hair in a high bun on the condition that the requirements mentioned above are met.

Allaah knows best.