The co-production of transition planning (i.e. care leavers having opportunities to influence decisions about their lives) is recognised as an important process internationally. However, little is known about factors influencing care leavers’ involvement in transition planning. This study uses a sample of care leavers in California (n = 423) and multiple data sources, including youth–worker matched data, to investigate predictors of transitional independent living plan (TILP) involvement. The outcome measures the mechanisms care leavers experienced during their TILP process, including worker-driven production (i.e. not aware of or not involved), youth-driven co-production (i.e. involved in and led) and youth–worker co-production (i.e. involved in but did not lead). Multinomial logistic regression was used to examine relationships between predictors measured at age 17 and TILP involvement mechanisms at age 19. Most youth led (44 per cent) or were involved in (43 per cent) TILP planning, but 14 per cent were not aware or uninvolved. Care leavers’ opportunities to influence their TILP were shaped by their individual (e.g. personality and support networks), relational (e.g. caseworker’s perception of youth’s preparedness) and contextual (e.g. regional service availability) factors. Notably, youth served by specialised caseworkers were more likely to experience youth–worker co-production than youth-driven co-production. Implications for practice and research are discussed.