This study examines the effect of Foreign Direct Investment (FDI) and trade openness on a firm’s export competitiveness and diversification among East African Community (EAC) members. Unlike previous studies, we investigated this issue to emerging region of EAC. The study uses traditional panel methods of fixed and random effect for the sample period 2010–2019. On one front, the effect of FDI on a firm’s export competitiveness and trade diversification were positive and statistically significant. On the other front, the effect of trade openness was positive and statistically significant only to export diversification but insignificant to export competitiveness. All results are robust to the alternative dependent variable, control variable, and sample size. Policy reforms to improve economic freedom, technological development, and strengthening the inter-relationship of the domestic sector with FDI and trade openness are required to improve export competitiveness and diversification.