Peptide vaccination for breast cancer aims to elicit a tumor-specific active immune response, with simple administration and limited toxicity. Despite promising immunologic data, clinical results continue to be mixed. Principles of cancer vaccine development include identification of appropriate tumor antigens with derivation of immunogenic epitopes, followed by selection of delivery method and immunoadjuvant such as granulocyte-macrophage colony-stimulating factor (GM-CSF). Challenges of peptide vaccination for cancer include overcoming immunotolerance, selecting appropriate patient populations, and measuring meaningful impact in clinical trials. Future investigation into individually tailored vaccines targeting neoantigens and use of vaccines as a component of combination immunotherapy show promise in the immunotherapy approach for breast cancer.