Mealtimes in families with young children are increasingly of interest to nutrition and public health researchers, yet assessment tools are limited. Meals in Our Household is a new parent-report questionnaire that measures six domains: 1) structure of family meals, 2) problematic child mealtime behaviors, 3) use of food as reward, 4) parental concern about child diet, 5) spousal stress related to child's mealtime behavior, and 6) influence of child's food preferences on what other family members eat. Reliability and initial face, construct, and discriminant validity of the questionnaire were evaluated between January 2007 and December 2009 in two cross-sectional studies comprising a total of 305 parents of 3- to 11-year-old children (including 53 children with autism spectrum disorders). Internal consistencies (Cronbach's α) for the six domains averaged .77 across both studies. Test-retest reliability, assessed among a subsample of 44 parents who repeated the questionnaire after between 10 and 30 days, was excellent (Spearman correlations for the domain scores between two administrations ranged from 0.80 to 0.95). Initial construct validity of the instrument was supported by observation of hypothesized inter-relationships between domain scores that were of the same direction and similar magnitude in both studies. Consistent with discriminant validity, children with autism spectrum disorders had statistically significantly (P<0.05) higher domain scores for problematic child mealtime behaviors, use of food as reward, parental concern about child diet, and spousal stress, as compared to typically developing children. Meals in Our Household may be a useful tool for researchers studying family mealtime environments and children's mealtime behaviors.