Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts shown to play important roles in tumourigenesis and tumour progression. Our study aimed to examine expression of the lncRNA MAGI2-AS3 in breast cancer and to explore its function in cancer cell growth. First, MAGI2-AS3 expression levels in clinical samples and cell lines were determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The functional significance of MAGI2-AS3 in cancer cell proliferation and apoptosis was then examined in vitro. Our results showed MAGI2-AS3 to be down-regulated in breast cancer tissues compared to normal adjacent tissues. Moreover, MAGI2-AS3 markedly inhibited breast cancer cell growth and increased expression of Fas and Fas ligand (FasL). In conclusion, our data suggest that MAGI2-AS3 expression is decreased in breast cancer and that MAGI2-AS3 plays an important role as a tumour suppressor by targeting Fas and FasL signalling. These results provide new insight into novel clinical treatments for breast cancer.