Background: Breast cancer (BC) is the leading cause of death in women worldwide. Golgi membrane protein 1 (GOLM1) has been identified as novel regulator in carcinogenesis, but its function in BC is unclear. Material/Methods: The expression of GOLM1 in BC tissues and cell lines was detected by using qRT-PCR assay. CCK-8 and colonyformation assays were used to evaluate BC cell growth in vivo. Wound-healing and Transwell assays were used to detect cell migration and invasion. To investigate GOLM1 functions in vivo, we established a xenograft mice model and a lung metastasis model. The level of epithelial-to-mesenchymal transition (EMT)-related markers was analyzed by immunofluorescent staining. Result: GOLM1 was overexpressed in BC cell lines and tissues. Overexpression of GOLM1 induced EMT and promoted proliferation, migration, and invasion of BC cells. Furthermore, overexpressing of GOLM1 markedly promoted the tumorigenicity and metastasis of BC cells in vivo, whereas knock-down of GOLM1 caused the opposite outcomes. Furthermore, we proved that GOLM1 promoted BC cell aggressiveness by regulating matrix metalloproteinase-13 (MMP13). Conclusions: Our results prove that GOLM1 facilitates the growth and metastasis of breast cancer cells.