This paper attempts to link industry and national contexts to the joint efect of product and international diversifcation on frm performance. Te research on how frm performance is afected by diversifying into new product and geographic markets has been an important topic of international business and strategy literature for more than 40 years (Bowen & Sleuwaegen, 2017; Castellani, Montresor, Schubert, & Vezzani, 2017). Product and international diversifcation are vital strategies in organisation expansion (Kistruck, Qureshi, & Beamish, 2013). Despite the fact that increasing number of frms have been engaging in the both diversifcation strategies, few papers study the interaction between the two diversifcation strategies and its performance implications. Most previous papers only focus on one type of diversifcation. Furthermore, those studies that do consider the joint efect of the two diversifcation strategies on frm performance (Geringer, Tallman, & Olsen, 2000; Hitt, Hoskisson, & Kim, 1997; Kistruck et al., 2013; Sambharya, 1995) identify either a complementary or a substitute efect between two diversifcation strategies. Tey generally ignore, however, the underlying factors that strengthen or weaken the joint efect. Product and international diversifcation have two opposing interactive efects, namely complementary and substitute efects, on frm performance. On the one hand, the complementary efect suggests that the sophisticated managerial capabilities developed in managing multiple product divisions can be easily leveraged in multiple geographic markets. On the other hand, the substitute efect contends that resource constraints would require the frm to choose between the two diversifcation strategies, suggesting a tradeof. Previous empirical papers provide mixed results regarding the interaction efect of two diversifcation strategies, including not signifcant, positive or negative efects (Geringer, Beamish, & DaCosta, 1989; Hitt et al., 1997; Sambharya, 1995). We contribute to this debate by examining the joint efect of two diversifcation strategies. More importantly, we further examine how industry and national contexts shape the relationship between the two diversifcation strategies and frm performance, particularly considering the technological capability of the home sector and the economic development of home country.