Abstract Background The impact of parental problem gambling on children and adolescents encompasses negative outcomes in psychological, financial, behavioral, physical health, and family relationship domains. For Germany, estimates on the number of co-affected minors are lacking. Methods Within the population-representative Germany-wide “Glücksspielsurvey 2023” (i.e., “Gambling Survey 2023”), we assessed parenthood in survey participants with gambling disorder (GD; according to DSM-5) as well as the number of minors (age <18 years) living a) together with a person with gambling disorder (shared household) or b) apart from a parent with gambling disorder (separate household). Using a “minimum maximum approach,” we performed a weighted extrapolation to estimate the number of co-affected minors in the German resident population (range 18 to 70 years of age) and the prevalence of parental GD among Germany-residing minors. Results 46.8% (n = 132) of survey participants with GD report shared households with minors and 16.3% (n = 46) separate households. The average number of minors concerned was 1.55 (SD = 0.07) in shared and 1.51 (SD = 0.13) in separate households. This translates into 480,294 to 701,766 co-affected children in shared households (3.4% to 4.9% of Germany-residing minors) and 91,742 to 124,618 co-affected children in separate households (0.6% to 0.9% of Germany-residing minors). Discussion and conclusions Taking shared and separate households into account, one in 20 Germany-residing minors is co-affected by parental GD. Acknowledging that impaired psychosocial wellbeing in the context of parental GD could persist into adulthood of co-affected minors, this issue ought to be recognized as a major public health concern. To reduce related harm, children of people with GD should be best possibly integrated into the care process by offering additional help and support strategies explicitly addressed at this vulnerable population. Key messages • Parental problem gambling significantly impacts a substantial portion of German minors, with approximately one in 20 being affected, highlighting the urgent need for attention to this issue. • Recognizing parental gambling’s long-term impact on minors, it’s crucial to implement support strategies in care to address their needs effectively.