Various factors limit the use of simvastatin as an anticancer drug. Therefore, this study aimed to analyse simvastatin (SIM)-loaded cubosome efficacy against breast cancer. SIM-loaded cubosomes were prepared using the emulsification method using different glyceryl monooleate, Pluronic F127 (PF-127), and polyvinyl alcohol (PVA) ratios. The best cubosomal formula was subjected to an in vitro cytotoxicity analysis using the human breast cancer cell line, MDA-MB-231 (MDA) (ATCC, HTB-26), and formulated as oral disintegrating tablets through direct compression. PF-127 and PVA positively affected drug loading, and the entrapment efficiency percentage of different SIM-cubosomal formulations ranged from 33.52% to 80.80%. Vesicle size ranged from 181.9 ± 0.50 to 316.6 ± 1.25 nm. PF-127 enhanced in vitro SIM release from cubosome formulations due to its solubilising action on SIM. The in vitro dissolution analysis indicated that SIM exhibited an initial dissolution of 10.4 ± 0.25% within the first 5 min, and 63.5 ± 0.29% of the loaded drug was released after 1 h. Moreover, cubosome formula F3 at 25 and 50 µg/mL doses significantly decreased MDA cell viability compared to the 12.5 µg/mL dose. The untreated SIM suspension and drug-free cubosomes at all doses had no significant influence on MDA cell viability compared to the control.