Triple-negative breast cancer (TNBC) represents the most aggressive breast carcinoma subtype lacking efficient therapeutic options. A promising approach in cancer treatment is the pharmacological inhibition of murine double minute 2 (MDM2)-p53 interaction inducing apoptosis in p53 wild-type tumors. However, the role of MDM2 in TNBC with primarily mutant p53 is not well understood. We here selected the clinical-stage MDM2 inhibitors Idasanutlin and Milademetan and investigated their anti-tumoral effects in TNBC. When we analyzed anti-tumor activity in the TNBC cell lines MDA-MB-231, MDA-MB-436, and MDA-MB-468, cellular viability was efficiently reduced, with half maximal inhibitory concentration (IC