多國企業的研究於國際企業之領域已行之多年，然而關於亞洲多國企業及其績效之探討尚未受到廣泛的注意。本研究以台灣大型製造廠商為樣本，探討國際化程度與產品差異化能力對廠商績效的影響。經由分析行政院主計處製造業資料庫發現，產品差異化能力 (包括研發密集度及廣告密集度) 對台灣的廠商績效有正向的影響。鑑於過去研究專注於線性關係的探討，本研究檢驗國際化程度對績效的影響為一先增後減的關係。實證結果發現，國際化程度與廠商績效間確實存在著倒 U 型的關係，即當國際化程度超過最適水準時，會使廠商績效產生負向效果。 The literature on multinational corporations (MNCs) lacks in depth study of Asian MNCs and the factors affecting their performance. This study examined the relationship of performance with internationalization and capability for product differentiation. By analyzing the internationalization activities of large Taiwanese firms, we found that the capability for product differentiation (in terms of R&D intensity and advertising intensity) has a positive impact on firms’ performance. In contrast to prior research that assumes a linear and monotonic relationship, this paper examined a curvilinear relationship between internationalization and performance. Empirical results showed that increasing levels of internationalization generate positive impact on performance up to specific level. Beyond the level, internationalization has a negative impact on the performance of large Taiwanese manufacturing MNCs. In short, an inverted U-shaped relationship between internationalization and performance was supported.