The coronavirus (COVID-19) pandemic has impaired young children's mental health, underscoring the need for research on protective factors. Using a cross-sectional design, we examined whether parental working memory (WM) buffered relations between COVID-19 hardships (home-life, economic, and quarantine) and child internalizing and externalizing symptoms. Female parents ( N = 339; 83.19% White/Caucasian, 8.85% Black/African American, 3.54% Asian, 1.47% Native American, and 2.36% mixed race; 7.67% Hispanic/Latinx ethnicity) of children 2-5-years-old reported COVID-19 hardships and child internalizing and externalizing symptoms and completed a backward digit span task to measure WM. All types of COVID-19 hardships were positively related to child internalizing and externalizing symptoms. Higher parental WM weakened positive relations between all types of hardships and child internalizing symptoms, and between home-life and economic hardships and externalizing symptoms. Results suggest that parental WM, a malleable target for intervention, may buffer associations between the detrimental effects of COVID-19 and young children's mental health.