The objectives of this study are to (1) characterize patterns of preventive behaviors 3 months after the COVID-19 pandemic was declared a national emergency in the USA and (2) identify how health beliefs (e.g., perceived risk of infection, perceived risk of death upon infection, and perceived effectiveness of CDC-recommended preventive behaviors) and sociodemographic characteristics are associated with preventive behaviors. Data were obtained from two waves of the Understanding America Study (UAS) conducted in March (wave 1) and May to June of 2020 (wave 2) (n = 4445); UAS is a nationally representative panel of US adults. We conducted a latent class analysis (LCA) using wave 2 data to identify our outcome, patterns of 10 COVID-preventive behaviors (e.g., wearing a facemask, handwashing, social distancing), and then used a three-step regression (R3STEP) to test associations between the likelihood of class membership with (1) health beliefs and sociodemographic characteristics (age, sex, race/ethnicity, and educational attainment) in bivariate models and (2) health beliefs adjusted for sociodemographic characteristics in multivariate models. The LCA identified a three-class model of preventive behaviors characterized by high likelihood of engagement in the set of preventive behaviors (“high”), low likelihood of the preventive behaviors (“low”), or engagement in some behaviors (“mixed”). Respondents of older age (i.e., age 50 or older) and those with higher levels of educational attainment (i.e., a 4-year college degree or higher) were less likely to be in the low engagement versus the mixed engagement class compared to those who are younger (18–29) and have lower levels of educational attainment (i.e., high school), respectively. Women (compared to men) and respondents who were Black and/or Hispanic/Latinx (compared to White) were more likely to be in the high (vs. mixed) engagement class. In separate models adjusted for sociodemographic characteristics, respondents with a high perceived risk of infection, high perceived risk of death, and high perceived effectiveness of COVID-preventive behaviors were statistically significantly less likely to be in the low engagement relative to the mixed engagement class. Engagement in COVID-preventive behaviors varies by sociodemographic characteristics (i.e., age, sex, race/ethnicity and educational attainment) and health beliefs (i.e., perceived risk of infection, perceived risk of death, and perceived effectiveness of CDC-recommended behaviors). Our findings highlight the potential utility of using health beliefs to inform targeted prevention efforts to help reduce the spread of COVID-19 and future pandemics.