Background: Oral disorders are a major cause of nonfatal disability, whereas lip and oral cavity cancer (LOCC), classified separately under neoplasms in the Global Burden of Disease (GBD) hierarchy, contributes both fatal and nonfatal burden. We assessed their national and subnational burden in Iran from 1990 to 2021.

Methods: GBD 2021 estimates were extracted for Iran and its 31 provinces. The analysis included caries of deciduous and permanent teeth, periodontal diseases, edentulism, other oral disorders, and LOCC. Age-standardized incidence, prevalence, mortality, years lived with disability, years of life lost, and disability-adjusted life years (DALYs) were examined. Changes in absolute counts were decomposed into population growth, age-structure change, and rate change. Age–period–cohort models were fitted for LOCC incidence and mortality.

Results: The DALY rate for oral disorders was 318.38 per 100,000 in 2021 versus 314.99 in 1990 (+1%), indicating a high but largely stable burden. LOCC incidence increased from 0.61 to 0.94 per 100,000 (+54%), prevalence from 1.69 to 3.48 (+106%), mortality from 0.40 to 0.46 (+14%), and DALYs from 9.63 to 10.79 (+12%). Men had higher DALY rates for LOCC and oral disorders, and both burdens increased with age. Provincial variation was greatest for LOCC. Oral-disorder counts increased mainly because of population growth, whereas LOCC incidence and deaths increased through demographic and rate changes. Age–period–cohort models showed adverse period effects from the 2010s and limited cohort effects.

Conclusions: Iran faces two distinct oral-health challenges: a high and persistent disability burden from oral disorders and a smaller but increasing burden from LOCC. Condition-specific prevention, equitable access to essential oral care, tobacco control, early detection, and improved surveillance are required.