Introduction The tobacco endgame, policies aiming to end the commercial tobacco epidemic, requires sustained public support, including among youth. We assessed endgame support among California (USA) adolescents, including their reasons and associated participant and policy-specific factors.

Methods Teens, Nicotine and Tobacco Project online surveys (n=4827) and focus groups were conducted in 2021 and 2022 among California residents aged 12–17 years. Cross-sectional survey participants were asked their agreement level with eight policy statements related to tobacco and/or cannabis sales restrictions, use in public places and use in multiunit housing. Ordered logistic regression modelled level of agreement according to respondent characteristics, behaviours and statement content. Qualitative data were collected through focus groups (n=51 participants), which were analysed to provide insight into support for different policies.

Results Most survey participants agreed or strongly agreed with tobacco product sales restrictions (72%–75%, depending on the policy), bans on use in public spaces (76%–82%) and smoke-free (79%) and vape-free (74%) apartment buildings. Support was stronger among younger, female, Asian and tobacco non-using participants and for policies directed at ‘tobacco’ (vs ‘vapes’ or cannabis), at flavoured tobacco (compared with all tobacco), and when statements featured ‘should end’ (vs ‘not allowed’). Focus group participants who were supportive viewed policies as protecting children from harmful products, while those less supportive cited concerns about limiting adults’ freedoms and unintended consequences.

Conclusions Most participants supported strong tobacco control policies. Public communication that promotes broader endgame benefits besides protecting youth and accelerates industry denormalisation may counter youth concerns and further bolster their support.