To describe and identify the correlates of firearm purchasing at the beginning of the COVID-19 pandemic among US families with teenagers. In June–July 2020, we conducted a national survey of 2924 parents and their teenagers in the US. We report results from this survey to describe firearm purchasing behaviors following the start of the COVID-19 pandemic and investigate correlates of purchasing. Between the beginning of the pandemic and July 2020, 10% of households with teenagers purchased a firearm, and 3% became first-time firearm-owning households. Among firearm-owning households, firearm storage was associated with purchasing such that households that stored at least one firearm loaded and unlocked were more likely to purchase a firearm (OR: 2.02[1.07–3.79]) compared to households that stored all firearms unloaded and/or locked. Firearms purchased at the beginning of the pandemic were more likely to go to homes where at least one firearm was stored loaded and unlocked, which may contribute to increased risk for teen firearm injury and death.