A combination of experimental and computational studies have identified a C=O•••isothiouronium interaction as key to efficient enantiodiscrimination in the kinetic resolution of tertiary heterocyclic alcohols bearing up to three potential recognition motifs at the stereogenic tertiary carbinol center. This discrimination was exploited in the isothiourea-catalyzed acylative kinetic resolution of tertiary heterocyclic alcohols (38 examples, s up to > 200). The reaction proceeds at low catalyst loadings (generally 1 mol%) using either isobutyric or acetic anhydride as the acylating agent under mild conditions.