This invention relates to humaneered anti-factor B antibodies and antigen-binding fragments thereof with reduced immunogenicity. The humaneered anti-factor B antibodies and antigen-binding fragments thereof are derived from murine monoclonal antibody 1379, which binds factor B in the third short consensus repeat (“SCR”) domain and selectively inhibits activation of the alternative complement pathway by preventing formation of the C3bBb complex. The invention also relates to methods of treating diseases or disorders in which activation of the alternative complement pathway plays a role, and methods of selectively inhibiting activation of the alternative complement pathway in an individual in need thereof.