AbstractGamma (γ‐T3) and delta (δ‐T3) tocotrienols are the most potent natural protective agents against harmful effects of radiation exposure and there is substantial interest in advancing these tocols toward Food and Drug Administration approval. However, co‐administration with alpha tocopherol is reported to interfere with the radioprotective properties of the tocotrienols. The objective of this study was to test various flash chromatography conditions for the purification of fractions with a high proportion of γ‐T3 or δ‐T3 and a minimal amount of alpha isomers from tocol extract obtained from rice bran oil deodorizer distillate (RBODD). Load size (0.125, 0.250, 0.500 and 1.000 g), sample cartridge type (pre‐packed silica cartridge, empty cartridge+Celite 545) and mobile phase gradient [varying proportions of hexane–acetic acid (99.1:0.9 v/v) and ethyl acetate–acetic acid (99.1:0.9 v/v)] were evaluated. Peak resolution was best with a load size of ~1 % column capacity and a 5‐g silica sample cartridge coupled with a 12‐g silica column. A linear gradient of 0.8 % ethyl acetate–acetic acid (99.1:0.9 v/v) to hexane–acetic acid (99.1:0.9 v/v) (50 min) → 100 % ethyl acetate–acetic acid (99.1:0.9 v/v) (5 min) resulted in the best separation of tocols. The method developed was used to isolate tocols from samples of crude RBODD, tocol concentrate and tocol‐rich extract. The use of these conditions with a tocol‐rich extract resulted in several fractions containing 100 % purities of both γ‐T3 and δ‐T3.