We examine whether the impacts of COVID-19 on labor supply differ across women with different degrees of childcare burden during the initial stage of the pandemic in South Korea. To identify the effect of the outbreak, we exploit the fact that the first wave of the outbreak in South Korea was concentrated in a specific region due to a largescale religious gathering. Utilizing the Local Area Labour Force Survey, we find that the negative impact was larger for women with young children than for women without young children. Specifically, our preferred specification suggests the employment rate of women with young children decreased by 3.9 percentage points more than that of women without young children due to the COVID-19 outbreak. Women with young children also reduced weekly working hours more than their counterparts without young children. Unlike women, the impacts of COVID-19 on the labor supply among men with and without young children were not different.