The main purpose of this paper is to extend conventional capital structure theory and provide some unique empirical evidences in terms of 159 electronics firms listed on the Taiwan Stock Exchange over the 2004-2006 period. This 159 electronics firms have divided into four high and/or low internationalization/diversification strategy sub-groups (i.e., H-H, H-L, L-H, and L-L strategy sub-groups). By using quantile regression, we integrate conventional firm-specific financial determinants, diversification and internationalization into capital structure models. Our results show that, for firms which adopt the H-H, H-L and L-H strategies, the product line diversification is positively correlated with the firms' debt ratios. On the other hand, the business segments diversification and reinvested business unit diversification are negatively correlated with the firms' debt ratios. However, for the L-L strategy firms, the diversification and debt ratios are negatively correlated. For the H-H strategy and H-L strategy firms, the foreign sales ratio internationalization is positively correlated with the firms' debt ratios, but the overseas markets internationalization is negatively correlated with the firms' debt ratios. For the L-L strategy firms, the internationalization and debt ratios are negatively correlated. In general, diversification and internationalization exhibit an inverted V-shaped or U-shaped influence on the debt ratio quantiles.