More and more researches have shown the vital functions of long non-coding RNAs (LncRNAs) in modulating the biological progresses in tumorigenesis. OR3A4 is such a type of lncRNA. The long non-coding RNA (lncRNA) OR3A4 has recently been exposed to be exceptionally expressed and referred to the development of several cancers. Nevertheless, the biological function and clinical significance of OR3A4 in the carcinogenesis of breast cancer (BC) are still blurry. Therefore, we carried out the following study to make sure the underlying functions of OR3A4 in breast cancer. In this article, by means of qRT-PCR assay, we found that OR3A4 was over-expressed in human breast cancer tissues and cell lines and associated with clinicopathological characteristics. In addition, we also found that the silence of OR3A4 suppressed the proliferation of breast cancer cells by influencing cell cycle and apoptosis, and repressed the cell metastasis via EMT, which was contrary to the results in cells transfected with pcDNA-OR3A4. And all the functions of OR3A4 in breast cancer were realized in the transcriptional level according to the subcellular fractionation location assay. Thus, based upon all of the data above, our study might provide a better understanding of the pathogenesis of breast cancer and implied that OR3A4 might be a potent prognostic and therapeutic target in breast cancer.