Workers holding intermediate hierarchical positions in an institution may have a higher risk of occupational stress-related, ill health. This study examined the prevalence rates and odds ratios (ORs) of anxiety disorders among a hierarchical group of firefighters. This cross-sectional study samples firefighters from Minas Gerais, Brazil, who answered a structured questionnaire in 2011 (survey completion rate = 89.5%). The outcome of interest was a medical diagnosis of anxiety disorder. Bivariate and multivariate analyses were conducted among five hierarchical occupational positions: privates (lowest position), corporals, sergeants (intermediate position), sub lieutenants, and officers (highest position). Overall, 8.4% of the sample reported an anxiety disorder, with the highest rate observed among intermediate workers (sergeants = 14.2%), followed by corporals (10%), privates (5.6%), sub lieutenants (5%), and officers (2.1%). Compared with privates, the unadjusted OR for sergeants was 2.49 (95% confidence interval, 1.35, 4.58). This finding remained statistically significant after adjustment for several control variables but was eliminated by age. The mental health of firefighters is affected by social class position. Mental health promotion efforts should focus on longitudinal research and work toward interventions aimed at modifying the hierarchical structure of workplaces.