Heat shock proteins (Hsps) are a group of stress-induced proteins that play crucial roles in protein folding and maturation. In breast cancer, Hsps regulate cell reactions and functions such as proliferation, metastasis, and apoptosis. This review systematically summarizes the roles of major Hsps (Hsp27, Hsp40, Hsp60, Hsp70, Hsp90, and Hsp110) in breast cancer biology and their potential uses in diagnosis and therapy. Hsp27, Hsp70, and Hsp90 are particularly high-expressed in breast cancer cells and are associated with poor prognosis. Hsp27 is involved in proliferation, metastasis, and drug resistance, while Hsp70 and Hsp90 regulate client protein stability and immune responses. Hsp40 has dual functions as both tumor suppressor and promoter, and Hsp110 acts as an adjuvant in immunotherapy. Pharmacological inhibition of these Hsps may provide therapeutic opportunities, but challenges remain, including the development of more selective inhibitors and the need for further research to understand their roles in normal cells. Understanding the functions and molecular mechanisms of Hsps is essential for improving breast cancer diagnosis and treatment.Heat shock proteins (Hsps) are a group of stress-induced proteins that play crucial roles in protein folding and maturation. In breast cancer, Hsps regulate cell reactions and functions such as proliferation, metastasis, and apoptosis. This review systematically summarizes the roles of major Hsps (Hsp27, Hsp40, Hsp60, Hsp70, Hsp90, and Hsp110) in breast cancer biology and their potential uses in diagnosis and therapy. Hsp27, Hsp70, and Hsp90 are particularly high-expressed in breast cancer cells and are associated with poor prognosis. Hsp27 is involved in proliferation, metastasis, and drug resistance, while Hsp70 and Hsp90 regulate client protein stability and immune responses. Hsp40 has dual functions as both tumor suppressor and promoter, and Hsp110 acts as an adjuvant in immunotherapy. Pharmacological inhibition of these Hsps may provide therapeutic opportunities, but challenges remain, including the development of more selective inhibitors and the need for further research to understand their roles in normal cells. Understanding the functions and molecular mechanisms of Hsps is essential for improving breast cancer diagnosis and treatment.