Background Many knowledge gaps exist in the area of alcohol-related harms in children research such as the potential impact of other’s drinking and their social demography. Thus, this study aims to evaluate the effects of characteristics of household members and others’ alcohol drinking on harms to children in Thailand. Data and methods This study examined 952 parents caring for children and adolescents under 18 years of age, using the questionnaire (i.e., The Harm to Others from Drinking under the WHO/ThaiHealth International Collaboration Research Project). They were interviewed between September 2012 and March 2013. Results The study found that 15.89% of children and young people were affected by someone’s drinking in at least one category of harms. People over 60 years of age were less likely to cause alcohol-related harm to children than those aged 18 to 29 (adjusted odds ratio [AOR] 0.19, 95% confidence interval [Cl]: 0.06–0.58). Households with a binge drinker or regular drinker (≥1 time/week) were more likely to have children at higher risk of suffering alcohol-related harm in comparison to households without alcohol drinker (AOR 4.75 and 1.92, respectively). Conclusion This study found that children whose family members are young adult or consume alcohol (i.e., weekly drinker or binge drinker) were significantly adversely affected. The most common problems were domestic violence and verbal abuse. Most of the problems, affecting children, were caused mostly by their parents.