In the title molecule, C13H15FN2S, the dihydropyrimidine ring is in a flattened boat conformation with deviations of 0.135 (2) and 0.371 (2) Å for the fluorophenyl-substituted N atom and the dimethyl-substituted C atom, respectively, from the four other essentially co-planar atoms. In the crystal, pairs of molecules related by twofold rotation axes are linked by N—H...S hydrogen bonds, forming dimers.