The present invention provides antibodies and antigen-binding fragments of antibodies that bind to leptin receptor (LEPR), and methods of using the same. According to certain embodiments, the invention includes antibodies and antigen-binding fragments of antibodies that bind LEPR and activate LEPR signaling. In other embodiments, the invention includes antibodies and antigen-binding fragments of antibodies that bind to LEPR and enhance sensitization of LEPR to an antigen. In certain embodiments, the invention includes antibodies and antigen-binding fragments of antibodies that bind LEPR in the presence and absence of leptin. In certain embodiments, the invention includes antibodies and antigen-binding fragments of antibodies that induce signaling in cells expressing LEPR mutants that otherwise exhibit defective or impaired signaling in the presence of leptin. The antibodies and antigen-binding fragments of the present invention are useful for the treatment of lipodystrophies and other diseases and disorders associated with or caused by leptin deficiency or leptin resistance.