Circular RNAs (circRNAs) act as pivotal functions in tumor progression. Nevertheless, the functions and mechanism of circRNAs in T-cell lymphoblastic lymphoma (T-LBL) remain unclear. In this work, we first screened the differentially expressed circRNAs between T-LBL tissues and normal infantile thymus and circ-LAMP1 was identified the highest expressed circRNA in cancerous tissues. qRT-PCR further verified its upregulation in T-LBL tissues and cell lines. Cell counting kit-8 (CCK-8) experiment proved the cell proliferation-promoting role of circ-LAMP1. This effect is partially dependent on its inhibition on cell apoptosis proved by flow cytometric assay. Dual-luciferase reporter system further identified that miR-615-5p could be sponged by circ-LAMP1 and discoidin domain receptor tyrosine kinase 2 (DDR2) 3′-UTR is the direct target of miR-615-5p. Rescue assays demonstrated that the biological function of circ-LAMP1 is partly attributed to the modulation of miR-615-5p/DDR2 signaling. In summary, these findings documented that circ-LAMP1 might be an oncogene in T-LBL, which might be useful in developing promising therapies for T-LBL.