HoxB7 is involved in cell migration and metastasis in many malignant tumors. But, the role of HoxB7 in lung adenocarcinoma has not been elucidated. In the present study, we aimed to clarify the function of HoxB7 in the progression of lung adenocarcinoma. The protein expression of HoxB7 was examined by immunohistochemical assay in human lung adenocarcinoma tissues, and lentivirus-mediated HoxB7 shRNA (Lv-shHoxB7) was transfected into lung adenocarcinoma cells to evaluate cell proliferation and invasive potential indicated by MTT and Transwell assays. As a result, the protein expression level of HoxB7 was increased in lung adenocarcinoma tissues compared with the adjacent non-tumor tissues (56.25% vs 31.25%, P=0.014), and was positively correlated with the lymph node metastasis in patients with lung adenocarcinoma (P=0.036). Moreover, knockdown of HoxB7 decreased the proliferation and invasion of lung adenocarcinoma cells followed by decreased expression of TGF-β/SMAD3, vascular endothelial growth factor A (VEGFA) and matrix metalloproteinase-2 (MMP-2). Taken together, our findings demonstrate that increased expression of HoxB7 is associated with tumor metastasis in patients with lung adenocarcinoma and HoxB7 may be implicated in promoting the development of lung adenocarcinoma through activation of the TGF-β/SMAD3 signaling.