Osteosarcoma is one of the most common primary malignant bone cancers in juveniles and adults. Increasingly, reports indicate that microRNAs (miRNAs) may provide novel therapeutic targets for cancer treatment. The aim of the present study was to investigate the expression of miR‑125a‑5p and to identify its functional significance in osteosarcoma. This indicated that miR‑125a‑5p was downregulated in osteosarcoma tissue and cell lines using reverse transcription‑quantitative polymerase chain reaction. Following transfection with miR‑125a‑5p mimics or the negative control, cell migration, invasion and epithelial‑mesenchymal transition (EMT) assays were conducted in osteosarcoma cells. These results indicated that the overexpression of miR‑125a‑5p resulted in inhibited osteosarcoma cell migration, invasion and EMT in vitro. Furthermore, mechanistic studies showed that matrix metallopeptidase‑11 (MMP‑11), was a direct target of miR‑125a‑5p in osteosarcoma. Taken together, the data demonstrate that miR‑125a‑5p functions as a tumor suppressor gene and serves an important role in inhibiting osteosarcoma cell migration, invasion and EMT by targeting MMP‑11.