**5. Conclusions**

The present review included studies that investigated the relationship between family functioning and happiness. The reviewed studies found a positive relation between happiness and family functioning in different cultures and age groups. Thus, family factors seem to play an essential role in increasing or diminishing the happiness of children and adolescents. However, many aspects remained largely unexplored, and more research is needed to determine how family variables (and particularly family functioning) affect children's and adolescents' happiness. Finally, more longitudinal studies are required to test causal relationships. Increased evidence of the potential direction of causality of these variables would extend our knowledge of happiness, as it is currently unclear whether family variables affect levels of happiness, positive affect, and life satisfaction, and whether these relationships are bidirectional.

**Author Contributions:** Conceptualization, R.B., F.I. and J.P. methodology, R.B., F.I. and J.P; validation, R.B., F.I. and J.P., formal analysis, R.B., F.I. and J.P; investigation, F.I.; resources, R.B., F.I. and J.P.; data curation, R.B., F.I. and J.P.; writing—original draft preparation, F.I.; writing—review and editing, R.B., F.I. and J.P.; supervision, R.B. and J.P.; project administration, R.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Ethics Committee of the Department of Developmental and Social Psychology, Sapienza University of Rome.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Articles and data will be made available to the corresponding author upon reasonable request.

**Conflicts of Interest:** The authors declare no conflict of interest.
