Despite a number of studies have emphasized the extensive role of microRNA (miRNA) in the development of multiple cancers, the role of miR-30a-5p in the progression of osteosarcoma (OS) and the underlying mechanism are still limited. We detected the expression level of MiR-30a-5p and forkhead box D1 (FOXD1) in Clinical OS specimens and found that miR-30a-5p was significantly decreased while FOXD1 was markedly increased. Dual luciferase assay confirmed that FOXD1 was directly regulated by miR-30a-5p. In vitro assay showed that inhibitior of FOXD1 suppressed cell proliferation, migration and invasion in MG63 and U2OS cells, while overexpression of FOXD1 promoted OS cell proliferation and migration. In vivo assay further showed the inhibition of tumor growth after knockdown of FOXD1. These results suggested that FOXD1 might play key roles in OS development and progression, and was negatively regulated by miR-30a-5p in OS. (C) 2018 Published by Elsevier Inc.