Eriocalyxin B (EriB), a potent ent-kaurene extracted from Isodon eriocalyx, has turned up as novel anti-cancer agent during recent years against a range of cancer types. TNBC (Triple negative breast cancer) is highly aggressive breast cancer, which is resistant towards current therapeutics due to absence of drug targets. Here, we have probed the molecular mechanism of EriB-induced apoptosis in TNBC (MDA-MB231) cells to check whether its anticancer activity is mediated by modulation of STAT3 and NF-ϰB. EriB induced apoptosis in MDA-MB231 cells via inhibiting NF-ϰBp65, STAT3 phosphorylation, increasing Bax/Bcl-2 ratio, MMP dissipation, and activation of caspase-3. These results provide a rationale for further in vivo investigations on EriB, which might also prove to be a potential drug candidate for developing novel therapeutics against TNBC.