Child anxiety and depression increased in recent years, while access to health care improved in some ways and worsened in others. The purpose of this study was to understand the prevalence of child anxiety and depression during the COVID-19 pandemic, unmet mental health care need among children with these conditions, and whether disparities exist by race/ethnicity and sex. A cross-sectional secondary data analysis was conducted using the 2021 National Survey of Children's Health (ages 3-17 years, unweighted n = 42,175). Parent/caregiver-reported child anxiety and depression prevalence was greater among non-Hispanic White children than those of other racial/ethnic groups and females compared to males, after adjusting for covariates. Unmet mental health care need among children with anxiety and depression was greater among Hispanic children than those of other racial/ethnic groups, after adjusting for covariates. In conclusion, this study identified a disparity in unmet need between Hispanic children and those of other races and ethnicities. Implications for policy and practice are discussed.