Objective: To explore whether thrombopoietin can exert a protective effect against doxorubicin-induced cardiotoxicity by modulating the sirtuin 1 (SIRT1) signaling pathway. Methods: H9c2 cell viability was determined by CCK-8 and cardiomyocyte apoptosis was detected by TUNEL assay. The protein expressions of SIRT1 and p38 MAPK were measured by Western blot. RT-qPCR was also used to determine S1RT1 mRNA expression. In addition, intracellular reactive oxygen species levels and antioxidant enzyme activities were evaluated. Results: Thrombopoietin treatment reversed doxorubicin-induced decline in H9c2 cell viability. It also increased SIRT1 and decreased p-p38 MAPK protein expressions. In addition, thrombopoietin significantly attenuated doxorubicin-induced apoptosis and oxidative stress, and enhanced antioxidant enzyme activities. However, silencing S1RT1 abrogated the protective effects of thrombopoietin, as evidenced by reduced cell viability and increased oxidative stress and reactive oxygen species levels. Conclusions: Thrombopoietin alleviates doxorubicin-induced cardiomyocyte injury by reducing oxidative stress and apoptosis via the SIRT1/p38 MAPK pathway. However, its protective effects need to be further verified in animal tests.