Plasma cell neoplasms are a group of disorders characterized by the abnormal proliferation of plasma cells, which are a type of white blood cell responsible for producing antibodies. These neoplasms are often associated with the development of monoclonal gammopathies, where an abnormal protein (M protein) is produced by the clonal plasma cells. The most well-known plasma cell neoplasm is multiple myeloma, a malignant condition that primarily affects bone marrow and bone. In multiple myeloma, the overgrowth of plasma cells can lead to bone destruction, anemia, kidney dysfunction, and susceptibility to infections. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma are precursor conditions that may precede the development of symptomatic multiple myeloma. Plasma cell neoplasms are diagnosed through laboratory tests, imaging studies, and bone marrow biopsies. Treatment approaches vary depending on the specific condition and its stage. Multiple myeloma may be treated with chemotherapy, immunomodulatory drugs, proteasome inhibitors, stem cell transplantation, and targeted therapies. While multiple myeloma remains incurable, advancements in treatment have significantly improved outcomes and quality of life for patients. Ongoing research continues to explore new therapeutic strategies and enhance our understanding of the underlying biology of plasma cell neoplasms. Early detection and intervention are crucial for managing these disorders effectively.