Local, state, and national laws and policies that limit the days of the week on which alcoholic beverages may be sold may be a means of reducing excessive alcohol consumption and related harms. The methods of the Guide to Community Preventive Services were used to synthesize scientific evidence on the effectiveness for preventing excessive alcohol consumption and related harms of laws and policies maintaining or reducing the days when alcoholic beverages may be sold. Outcomes assessed in 14 studies that met qualifying criteria were excessive alcohol consumption and alcohol-related harms, including motor vehicle injuries and deaths, violence-related and other injuries, and health conditions. Qualifying studies assessed the effects of changes in days of sale in both on-premises settings (at which alcoholic beverages are consumed where purchased) and off-premises settings (at which alcoholic beverages may not be consumed where purchased). Eleven studies assessed the effects of adding days of sale, and three studies assessed the effects of imposing a ban on sales on a given weekend day. The evidence from these studies indicated that increasing days of sale leads to increases in excessive alcohol consumption and alcohol-related harms and that reducing the number of days that alcoholic beverages are sold generally decreases alcohol-related harms. Based on these findings, when the expansion of days of sale is being considered, laws and policies maintaining the number of days of the week that alcoholic beverages are sold at on- and off-premises outlets in local, state, and national jurisdictions are effective public health strategies for preventing excessive alcohol consumption and related harms.