Thin-layer chromatography (TLC) and pressurized planar electrochromatography (PPEC) of amino acids in normal-phase system is presented. The results have been obtained for various normal-phase high-performance thin-layer chromatography (HPTLC) and PPEC systems with the mobile phase that comprised acetonitrile in the concentration ranges 40–90% and 20–90%, respectively, and HPTLC silica gel 60 F254s plates from Merck. The data obtained show differences in separation selectivity between HPTLC and PPEC systems. The respective separation selectivities have been obtained for HPTLC and PPEC systems with the mobile phase buffer pH in the range 2.6–9.0. The retention of amino acids in HPTLC systems has demonstrated minor dependence on buffer pH, while, in analogous PPEC systems, migration distances of the solutes have shown considerable changes. The differences of separation selectivity in HPTLC and PPEC systems are interpreted in terms of solute partition in the former and solute partition and electrophoresis in the latter.