Breast cancer is one of the most frequently occurring malignancies in female cancers worldwide, however, its detailed mechanism of tumorigenesis remains to be elucidated. Long non-coding RNAs (LncRNAs) have previously been demonstrated to be important in multiple cancers, including breast cancer. The present study aimed to elucidate the molecular mechanism of the effects of the novel Lnc RNA HOXA11‑AS, on cell proliferation and metastasis in breast cancer. The data revealed that the relative transcript level of HOXA11‑AS was upregulated in vivo and in vitro in models of breast cancer. Knockdown of HOXA11‑AS in MDA‑MB‑231 and MDA‑MB‑436 breast cancer cell lines inhibited the formation of cell colonies and arrested the cell cycle at the G0/G1 phase. Depletion of HOXA11‑AS using two specific short interfering (si)RNAs against HOXA11‑AS (siHOXA11‑AS‑1 and siHOXA11‑AS‑2) additionally suppressed the cell proliferative rate. Furthermore, transwell assays and wound‑healing analysis revealed that siRNA transfection inhibited cell migration and invasion by ~50% in the two cell lines. The results of the present study demonstrated the oncogenic role of HOXA11‑AS in breast cancer, providing novel clues for the future clinical diagnosis and treatment of early stage breast cancer patients.