This study compares the effects of international trade and fertility on the gender gap in the household workforce in Vietnam from 2002 to 2016. The results reveal that having children prevents women from entering the labor market, although international trade has opened more job opportunities for them. The ratio of working hours of wives to husbands only increases if their child is aged >6 years. Further, both international trade and fertility reduce the gender gap in working hours. However, regarding the gender pay gap, the impact of international trade is often more statistically significant than that of fertility. In addition, other factors that affect the participation of female workers include their education level, their husbands’ income, and whether they live with someone who can help take care of their children when they are unable to take care of them because of secular work.