Abstract Background Global migration is on the rise, and as a result, millions of children are left in their home countries while their parents migrate abroad. Little is known about the mental health of left-behind children (LBC) in Eastern Europe. The study addresses this research gap in Georgia, a leading migrant-sending country in the region. Methods Applying convergent parallel design, this mixed methods research integrates a qualitative study with schoolteachers from six public schools in Samegrelo and Guria regions (6 focus group discussions and 6 in-depth interviews) (i); a school survey with 933 adolescents (ii) from 18 public schools, (12-18 age group, internalizing and externalizing problems assessed with Aschenbach’s “Youth Self-Report” questionnaire), and a qualitative study using life-narrative interviews with 39 adolescents (iii). We analysed qualitative data using reflexive thematic analyses and applied multiple linear regression to analyse quantitative data. Results The Quantitative and qualitative findings converge in some respects while diverging in others. Schoolteachers perceive migratory separation as a traumatizing life event, making children vulnerable to mental health issues. Similarly, schoolchildren perceive separation from parents as a stressful life event; however, they also acknowledge positive aspects of migrant labour, such as material benefits. From the perception of LBC, close family ties, friendships, school support, and optimism help with coping. This study also revealed a gender disparity, with boys exhibiting more rule-breaking behaviour and girls performing worse on most Youth Self- Reported syndrome scales. Regression analysis showed associations between adolescents’ problem behaviours and relationships with family members, friendships, and school environment. Conclusions This research found that parental migration effects on children are complex and depend on individual and transnational family characteristics. Key messages • Left-behind children may need emotional and academic support. • Strengthening family ties, supportive school environment and friendships contribute to adolescents’ coping with parental migration.