Accumulating evidence has emerged important roles for microRNAs (miRNAs) participating in oncogenesis and growth of various cancers. We hypothesized that miR-661 played an important role in cell growth of ovarian cancer. Here, we found miR-661 was upregulated in human ovarian cancer cell lines and clinical tumor tissues. Our results revealed that miR-661 directly targeted INPP5J, thereby acting as tumor promoter in ovarian cancer cells by blocking cell proliferation. Importantly, we identified miR-661 as a positive regulator of INPP5J-induced AKT pathway. Taken together, our study sheds light onto the role of miR-661 as tumor promoter by targeting the INPP5J gene, and then promoting cell proliferation of ovarian cancer.