The human adenosine triphosphate (ATP)-binding cassette (ABC) subfamily G2 (ABCG2) half transporter of the G-subfamily that is involved in transportation of an extensive range of substrates, including xenobiotics and endogenous compounds. ABCG2 transporter upregulation in many cancerous tissues is often linked to multiple drug resistance (MDR) due to its involvement in efflux of various drugs. Gamma-tocotrienol (γT3) is an isoform of vitamin E that possesses promising anti-cancer effects via various mechanisms, however, transportation of γT3 remains unknown and its therapeutic effects might be limited by MDR. This project, thus, sought to study the anti-cancer effect (i.e. anti-proliferative effect) of γT3 in an ABCG2-expressing breast cancer cell line [Michigan Cancer Foundation-7-mitoxantrone (MCF7-MX)] and the possibility of γT3 to be transported via ABCG2 transporter. It was demonstrated that after 72 hr treatment with γT3, cell proliferation of MCF7-MX cells was inhibited with IC50=43 μM. The co-administration of γT3 with MX, a substrate of ABCG2, has shown that γT3 is not a competitor for MX transport (p>0.05). The data confirms the anti-proliferative role of γT3 in ABCG2 expressing cells and suggests that ABCG2 might have a minimal role in γT3 transport. This result provides an essential basis for the further study of γT3 as an anti-cancer compound.