Long non-coding RNAs (lncRNAs) are frequently dysregulated in multiple malignancies, demonstrating their potential oncogenic or tumor-suppressive roles in tumorigenesis. Herein, we reported the identification of a novel lncRNA, linc00665 (ENST00000590622), which was markedly upregulated in lung adenocarcinoma (LUAD) tissues and might serve as an independent predictor for poor prognosis. Functional assays indicated that linc00665 reinforced LUAD cell proliferation and metastasis in vitro and in vivo. Mechanistically, transcription factor SP1 induced the transcription of linc00665 in LUAD cells, which exerted its oncogenic role by functioning as competing endogenous RNA (ceRNA) for miR-98 and subsequently activating downstream AKR1B10-ERK signaling pathway. Together, our study elucidates oncogenic roles of linc00665-miR98-AKR1B10 axis in LUAD tumorigenesis, which may serve as potential diagnostic biomarkers and therapeutic targets.