Background: Shifting demographic trends in the United States (US) have resulted in increasing numbers of three-generation family households, where a child lives with a parent(s) and grandparent(s). Although similar demographic trends have been occurring in the United Kingdom (UK) and Australia, very little research has studied three-generation coresidence in these countries and no research has documented trends cross-nationally.

Objective: We investigate differences in the rates of three-generation coresidence in early childhood cross-nationally.

Methods: This study uses three longitudinal birth cohort studies to investigate cross-national differences in three-generation coresidence in early childhood: the Early Childhood Longitudinal Study - Birth Cohort for the US, the Millennium Cohort Study for the UK, and the Longitudinal Study of Australian Children - Birth Cohort.

Results: We find that nearly one-quarter of US children live in a three-generation household during early childhood, compared to 8% of children in the UK and 11% in Australia. Although there are large differences in the frequency of coresidence cross-nationally, we find that similar demographic groups live in three-generation households across contexts. In general, younger, less educated, lower income, and minority mothers are more likely to live in three-generation households in all three countries.