Objectives. To examine temporal trends in sexual identity and sociodemographic disparities in Sweden after gender-neutral marriage legislation in 2009.

Methods. We analyzed 3 cross-sectional surveys from the Stockholm Public Health Cohort (2010, 2014, 2021) that included 76 083 participants 16 years or older. Weighted Poisson regression was used to estimate associations between sexual identity and sociodemographic covariates. Survey weights and multiple imputation addressed sampling design and nonresponse.

Results. Bisexual identity doubled between 2010 and 2021, from 2.1% (95% confidence interval [CI] = 1.8%, 2.4%) to 4.3% (95% CI = 3.8%, 4.7%) among females and from 1.0% (95% CI = 0.8%, 1.2%) to 1.9% (95% CI = 1.6%, 2.3%) among males. In 2021, 15.1% (95% CI = 12.5%, 17.7%) of Generation Z (1997–2012) females and 6.9% (95% CI = 5.8%, 8.0%) of Millennials (1981–1996) identified as bisexual; the figures for males were 4.2% (95% CI = 2.8%, 5.7%) and 2.4% (95% CI = 1.7%, 3.1%). Bisexual identity was associated with lower income and never-married status, although the strength of the associations decreased over time.

Conclusions. The rise in bisexual identity, particularly among younger generations, likely reflects shifting societal and cultural norms. Income and marital disparities persist but have narrowed.

Public Health Implications. Public health should support bisexual individuals as part of broader efforts to promote equity amid evolving norms.