Objective This study validated two Dental Quality Alliance system-level measures of oral healthcare quality for children – caries-related emergency department (ED) visits and timely follow-up of those visits with a dentist – including formal validation of diagnosis codes used to identify caries-related ED visits and measurement of follow-up care. Methods The measures were specified for implementation with administrative claims data and validated using data from the Florida and Texas Medicaid and Children’s Health Insurance Programs. Measure specification testing and measure score validation used administrative data for 7,007,765 children. We validated the diagnosis codes in claims data by comparisons with manual reviews of 300 records from a Florida hospital ED and calculation of the kappa statistic, sensitivity, and specificity. Results Overall agreement in caries-related ED visit classifications between the claims data and record reviews was 87.7 percent with kappa = 0.71, sensitivity = 82 percent, and specificity = 90 percent. The calculated measure scores using administrative data found more than four-fold variation between programs with the lowest and highest caries-related ED visit rates (6.90/100,000 member months and 30.68/100,000 member months). The percentage of follow-up visits within 7 days and 30 days ranged from 22-39 percent and 34-49 percent, respectively. Conclusions These National Quality Forum endorsed measures provide valid methodologies for assessing the rate of caries-related ED visits, an important system-level outcome indicator of outpatient prevention and disease management, and the timeliness of follow-up with a dentist. There is significant variation in caries-related ED visits among state Medicaid programs, and most ED visits do not have follow-up with a dentist within 30 days.