A novel chemical exfoliation of perovskite-like KCa₂Nb₃O₁₀ utilising an amino acid intermediate is described. At first, amino acid intercalated layered perovskite is prepared by ion-exchange reaction between the interlayer protons in HCa₂Nb₃O₁₀ and cationic aminoundecanoic acid (H₃N⁺(CH₂)₁₀COOH; AUA) under an acidic aqueous solution (pH ca. 3). Upon intercalation, the basal spacing of HCa₂Nb₃O₁₀ expands from 14.7 Å to 30.4 Å to form a paraffin-like monolayer arrangement of interlayered AUA molecules between the perovskite slabs. Subsequent infinite expansion of the oxide layers, which eventually leads to the exfoliation of perovskite slabs (Ca₂Nb₃O₁₀) into elementary oxide nanosheets, is accomplished by a host–guest repulsive interaction induced by deprotonation of the carboxylic groups in the interlayered amino acid molecules with NaOH titration. This argument is supported by a gradual decrease in the X-ray intensities of (00l) reflections upon base titration. The base titration curve and the zeta (ζ) potential measurement as a function of pH suggest that the intralayer deprotonation of carboxylic groups occurs rapidly in the pH range 8–9. A significant spectral blue shift for the colloidal particles compared to the pristine HCa₂Nb₃O₁₀ in the UV-vis absorption spectra also substantiates the delamination of bulk oxide layers into individual monolayers. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) observations reveal the formation of two or three elementary layers through the lattice exfoliation.