The aim of the present study was to investigate the roles of microRNA-152 (miR-152) in the initiation and progression of breast cancer. The expression level of miR-152 was detected in human breast cancer tissue and a panel of human breast cancer cell lines using qRT-PCR. Results found that miR-152 expression was significantly downregulated in breast cancer tissue samples compared to adjacent noncancerous tissues as well as in breast cancer cell lines. Overexpression of miR-152 significantly suppressed breast cancer cell proliferation, migration, and invasion. Luciferase reporter assay results found that ROCK1 is a direct and functional target gene of miR-152 in breast cancer. In addition, downexpression of ROCK1 could inhibit breast cancer cell proliferation, migration, and invasion. These findings indicate that miR-152 inhibited breast cancer growth and metastasis through negative regulation of ROCK1 expression. These data suggest that miR-152/ROCK1 pathway may be a useful therapeutic target for breast cancer treatment.