Kelch-like protein-11 (KLHL11) immunoglobulin G (IgG) is a recently reported paraneoplastic autoantibody associated with rhombencephalitis, which commonly presents with ataxia, diplopia, vertigo, hearing loss, tinnitus, and gaze palsies. The association of this high-risk paraneoplastic autoantibody with testicular germ cell tumors is widely accepted, but it has not been associated with Müllerian tumors. In this study, we report a woman without a known germ cell tumor presenting with signs and symptoms suggesting autoimmune encephalitis. She was found to have metastatic ovarian serous carcinoma with KLHL11 immunoreactivity on histopathology. This case demonstrates a rare cancer association of KLHL11 IgG-seropositive rhombencephalitis with Müllerian tumor and highlights that this autoantibody can also be detected in female patients. Thus, this case expands on the current knowledge of KLHL11-related autoimmune encephalitis including the paraneoplastic presentation, associated tumor types, and management of this syndrome in women.