This study investigates demographic diversity in the boards of public firms quoted at Borsa Istanbul. The findings show that female directors are neither less educated nor less professionally qualified than male directors. However, consistent with the glass ceiling arguments, the percentage of female directors that are CEOs or chairmen is lower compared to male directors.  Also, a lower percentage of them are independent and serve on audit committees. The findings also show that a lower percentage of foreign directors are independent, busy and serve on audit committees compared to Turkish directors. In addition, directors that are CEOs, busy directors or independent directors are younger. However, chairmen of firms are older. Lastly, the findings show that firms with foreign directors have lower total advice quality, compared to firms with no foreign directors. However, firms with female directors do not have a significantly different advice quality, compared to firms with no female directors