Purpose <p>This study seeks to examine sexual and gender minority (SGM) cancer survivors’ quality of life (QoL) by age at diagnosis and time since diagnosis.</p> Methods <p>This secondary data analysis utilized 2014–2023 Behavior Risk Factor Surveillance Survey data. The survey respondents consisted of 1708 SGM cancer survivors and 56,184 heterosexual cisgender cancer survivors. Logistic regression models compared individual SGM cancer survivor groups to heterosexual cisgender survivors’ QoL while stratifying by age at diagnosis and time since cancer diagnosis. We adjusted models for sociodemographic characteristics, access to care, and survey year.</p> Results <p>Lesbian women’s and gay men’s QoL was similar to heterosexual men’s and women’s overall and when stratifying by time since diagnosis. However, after stratifying by age at diagnosis, both lesbian women and gay men had significantly greater odds of difficulty concentrating compared to their peers, when diagnosed at younger ages. Bisexual women and men as well as transgender survivors’ QoL, differed from heterosexual cisgender survivors’ overall and by both time since diagnosis and age at diagnosis.</p> Conclusions <p>Sexual and gender minority survivors’ QoL varied by age at diagnosis and time since diagnosis, indicating a dynamic vulnerability among SGM cancer survivors. Therefore, this study elucidates critical periods for targeted interventions that address the unique needs of SGM cancer survivors.</p> Implications for cancer survivors <p>We found that sexual and gender minority survivors’ QoL differs based on stages of life and time since diagnosis. These findings highlight the need for targeted support for sexual and gender minority survivors at times of their greatest vulnerability.</p>