There are few papers that analyse the determinants of South East Asian firm board size, though there is a literature focusing on the impact of board characteristics on firm value. This paper adds to this former literature, focusing on the determinants of board size for firms listed in Hong Kong, Indonesia, Malaysia, the Philippines, Singapore and Thailand. While it is apparent that large firms have large boards there is also more subtle cross-country variation concerning the impact of leverage and agency costs on board size. Finally, using pooled analysis there is evidence of a decrease in average board size for firms in the Philippines and Singapore over the sample period, 1999 to 2002, with increases in average board size evident for Indonesian firms over the same period.