Recent reports have indicated that circular RNA (circRNA) may regulate Lung adenocarcinoma (LAC) development. Our previous studies showed that hsa_circ_0012673 was up-regulated in a circRNA microarray. However, its expression level in LAC has not been verified, and the underlying molecular mechanisms in LAC are unknown. In this study, we found that the expression of hsa_circ_0012673 was up-regulated in LAC tissues compared to pair-matched adjacent non-tumor tissues (P = 0.0079), and that the expression level was associated with tumour size (P = 0.015). Furthermore, hsa_circ_0012673 was primarily localized in the cytoplasm and promoted cell proliferation of LAC cells by sponging miR-22, which targeted erb-b2 receptor tyrosine kinase 3 (ErbB3) in LAC. Hsa_circ_0012673 promotes LAC proliferation by suppressing miR-22, which targets ErbB3. (C) 2018 Elsevier Inc. All rights reserved.