Dollar stores have rapidly expanded their food offerings in recent years. These foods tend to be higher in calories and lower in nutrients, raising public health concerns, especially in rural and low-income areas where food-access challenges are often greatest. However, there is limited empirical evidence evaluating the impact of this expansion on household food purchases on a national scale. Using data from a yearly, nationally representative panel of approximately 50 000 households, we estimated the share of food purchases from 2008 to 2020 by store type and evaluated the role of dollar stores as food retailers in the United States. We found that dollar stores were the fastest-growing food retailers by household expenditure share (increasing by 89.7%), with rural growth outpacing growth elsewhere (increasing by 102.9%). Though dollar stores still represent a small share of national household food purchases (2.1% in 2020), they play an increasingly prominent role in food-at-home purchases for certain disadvantaged and rural communities. Understanding the quality of the foods they offer and how this may affect diet-related health outcomes is warranted. (Am J Public Health. 2023;113(3):331-336. https://doi.org/10.2105/10.2105/AJPH.2022.307193).