A structural investigation of composite films of self-assembling stearate ions (C18) in layered double hydrotalcite clay (LDH) was carried out by means of X-ray diffraction (XRD) analysis, gas chromatography (GC), elemental analysis, thermogravimetry (TG), differential thermal analysis (DTA), and inductive coupled plasma emission spectrometric analysis (ICP-AES). From these detailed characterization studies, it was found that C18 forms a well-aligned bilayer structure within the inorganic LDH layers absorbed by the H2O monolayers with a tilt angle of approximately 29 from the right angle of the layers. Moreover, two-dimensional XRD analysis shows the guest anions to be arranged in a distorted hexagonal packing orientation along the lateral axis.