This thesis focuses on corporate practices and policy pertaining to board diversity. In the work, three questions are examined at individual director, firm and national levels of analysis, including examining: (i) how changes to diversity in board composition affect firm performance; (ii) the role of male and female director interaction networks in the underrepresentation of women at the top of corporations; (iii) the effects of legislative measures, regulatory ‘'comply or explain'’ principles and voluntary policy measures and their associated enforcement, implementation and compliance dimensions.

Overall the findings indicate that promoting a purely numerical level of diversity in board composition is insufficient. Board diversity practices should be supplemented by other organizational practices to ease newcomers’ and minority (female) directors’ inclusion into interaction networks. In addition, nationwide policy frameworks can efficiently aid in enhancing gender diversity in corporate boards if an appropriate design of policy elements is in place.