The aim of the study was to evaluate the association between salivary anti-Porphyromonas gingivalisIgA antibodies and the leprosy reaction. The levels of salivary anti -P. gingivalisIgA antibodies, together with salivary flow and pH were measured in individuals diagnosed with leprosy and associated with the development of the leprosy reaction. Saliva was collected from 202 individuals diagnosed with leprosy at a reference leprosy treatment center, 106 cases with the leprosy reaction and 96 controls without the leprosy reaction. Anti -P. gingivalisIgA was evaluated by indirect immunoenzyme assay. Non-conditional logistic regression analysis was employed to estimate the association between antibody levels and the leprosy reaction. There was a positive statistically significant association between the levels of anti -P. gingivalisIgA and the presence of the leprosy reaction, controlling for confounders: age, sex, level of education and alcoholic beverage consumption: ORajusted: 2.55; IC 95%: 1.34–4.87. Individuals with leprosy who had high levels of salivary anti -P. gingivalisIgA had approximately twice as many chances of developing the leprosy reaction. The findings suggest a possible relationship between salivary anti -P. gingivalisIgA antibodies and the leprosy reaction.