This study focuses on the relationship between age structure and trade openness. We hypothesise that a higher share of the working‐age population in the total population increases trade openness, because the dependent population tends to spend more than the working‐age population on non‐tradable goods such as education and medical services. We estimate the effects of age structure on trade openness using panel data for 85 countries from 1991 to 2010. The empirical results show that the share of the working‐age population has a positive effect on trade openness. An increase in the share of the working‐age population is considered to be one factor that contributed to an increase in trade openness in the sample period.