Background. Adolescence is a critical period of child's development which challenges both parents and adolescent children. However, little research has been conducted to understand how parents raise up their children during transition from early to late adolescence, especially, parenting of Thai parents whose adolescents are healthy. Thus, the current study aimed at generating the substantive theory of parenting during adolescence in Thai context.

Methods. A grounded theory study design was chosen. Eighteen Thai parents of healthy late adolescents aged 18-20 years were semi-structured interviewed. Data collecting and analyzing, and memo writing were done simultaneously. Transcripts were analyzed by using the constant comparative analysis process.

Findings. The emergent basic social process named as “Strengthening adulthood and connectedness” was performed by parents toward their children through out the transitional period from early to late adolescence. This process consisted of three major processes that occurred simultaneously: first, ‘increasing child's adulthood'; second, ‘reinforcing connectednesses'; and the last ‘balancing control and freedom'. The overall aim of parenting process would be to protect the children from risks and harms in today's society and strengthen those becoming healthy late adolescents.

Conclusions. Adolescence is a challenge and usually necessitates changes in parenting process. The benefits of this study will assist nurses and other health care providers apply this substantive knowledge to promote effective parenting of adolescents with appropriate and culturally interventions. Future research will focus on testing this conceptual process with a large population that includes developing a measurement device of parenting process during adolescence suited for Thai culture.