Abstract Background: Intrinsic defects in lymphocyte signaling have been implicated in the pathogenesis of autoimmunity. SLAP has been shown to influence BCR levels and signaling in developing B cells. We hypothesize that SLAP deficiency will enhance the negative selection of autoreactive B cells leading to decreased autoantibody production. Methods: To test this hypothesis we immunized SLAP-deficient and wild-type BALB/c mice with a peptide mimitope for dsDNA that leads to the development of dsDNA antibodies and a systemic lupus erythematosus-like autoimmune disease. In addition, we used a second model where we generated SLAP-deficient mice expressing an autoreactive BCR heavy chain 3H9H/E56R (56R) that binds dsDNA to determine how SLAP deficiency impacts BCR repertoire selection and autoantibody production. Results: SLAP-deficiency led to decreased serum levels of dsDNA antibodies in both experimental systems with a 6-fold reduction in the mimitope treated mice and a 3-fold reduction in dsDNA antibodies in the SLAP-deficient 56R mice. Flow cytometric analysis of bone marrow B cell subsets in SLAP-deficient 56R mice revealed a 27% reduction in fraction D, 37% in E and a 2-fold reduction in F, with a 19% increase in lambda usage compared to controls. Conclusions: These data support the hypothesis that SLAP deficiency enhances negative selection of autoreactive B cells leading to decreased autoantibody production.