Purpose: This paper aims to focus on testing the long-run relationship between fish production and two main variables, the foreign direct investment inflow and the marine trade balance in Oman, which is one of the Arab Gulf countries, during the period 1985-2016. Design/methodology/approach: This study uses what known as the two-step Engle–Granger cointegration test to give evidence for the long-run relationship among the variables. Findings: The results show that there are a negative long- and short-run relations between fish production and marine trade balance; moreover, any shocks will be corrected within two periods at the most. Originality/value: This study is one of few studies in using the econometric models to study the impact of fish production on marine trade balance and foreign direct investment.