The retentions of 17 substituted symmetrical triazine derivatives were determined in reversed-phase thin-layer chromatography using 27 organic solvents miscible with water. The data matrix was evaluated by multivariate techniques. It was established that a higher solvent lipophilicity means a higher solvent strength, but the lipophilicity explains only about 67% of total variance. The influence of lipophilicity was the lowest with acetonitrile, tetrahydrofuran, methyl ethyl ketone, di-methylformamide and ethylene glycol. Ch 3 and CH 2 groups increased significantly and primary OH, COC and ▪ groups decreased the solvent strength. The presence and position of nitrogen and oxygen atoms and free hydroxyl groups govern the solvent selectivity in reversed-phase thin-layer chromatography.