Haloperidol is an anti-psychotic used for the treatment of schizophrenia or Tourette disorder. Here we report, by studying three large administrative health insurance databases, that haloperidol use is associated with a reduced risk of developing rheumatoid arthritis. A meta-analysis revealed a 31% reduced hazard of incident rheumatoid arthritis among individuals with schizophrenia or Tourette disorder treated with haloperidol compared to those treated with other anti-psychotic drugs. These findings suggest a potential benefit of haloperidol in rheumatoid arthritis and provide a rationale for randomized controlled trials to provide causal insights.