Monoclonal neutralizing antibodies are disclosed that specifically bind to the HIV-1 gp41 membrane-proximal external region (MPER). Also disclosed are compositions including the disclosed antibodies that specifically bind gp41, nucleic acids encoding these antibodies, expression vectors including the nucleic acids, and isolated host cells that express the nucleic acids. The antibodies and compositions disclosed herein can be used for detecting the presence of HIV-1 in a biological sample, or detecting an HIV-1 infection or diagnosing AIDS in a subject. In additional, the broad neutralization breadth of the disclosed antibodies makes them ideal for treating a subject with an HIV infection. Thus, disclosed are methods of treating and/or preventing HIV infection.