Objective: To analyse the relation between exposure to workplace sexual harassment and suicide, as well as suicide attempts.

Design: Prospective cohort study.

Setting: Sweden.

Participants: 86 451 men and women of working age in paid work across different occupations responded to a self-report questionnaire including exposure to work related sexual harassment between 1995 and 2013. The analytical sample included 85 205 people with valid data on sexual harassment, follow-up time, and age.

Main outcome measures: Suicide and suicide attempts ascertained from administrative registers (mean follow-up time 13 years).

Results: Among the people included in the respective analyses of suicide and suicide attempts, 125 (0.1%) died from suicide and 816 (1%) had a suicide attempt during follow-up (rate 0.1 and 0.8 cases per 1000 person years). Overall, 11 of 4095 participants exposed to workplace sexual harassment and 114 of 81 110 unexposed participants committed suicide, and 61/4043 exposed and 755/80 513 unexposed participants had a record of suicide attempt. In Cox regression analyses adjusted for a range of sociodemographic characteristics, workplace sexual harassment was associated with an excess risk of both suicide (hazard ratio 2.82, 95% confidence interval 1.49 to 5.34) and suicide attempts (1.59, 1.21 to 2.08), and risk estimates remained significantly increased after adjustment for baseline health and certain work characteristics. No obvious differences between men and women were found.

Conclusions: The results support the hypothesis that workplace sexual harassment is prospectively associated with suicidal behaviour. This suggests that suicide prevention considering the social work environment may be useful. More research is, however, needed to determine causality, risk factors for workplace sexual harassment, and explanations for an association between work related sexual harassment and suicidal behaviour.