UV-Vis spectrometry and quartz crystal microbalance were used to measure the growth of these films as a function of the number of bilayers deposited, while scanning electron microscopy and transmission electron microscopy were used to visualize the morphology of the thin film coatings on the cotton fabric. Nanocomposites formed of cationic starch (CS) and clay introduced fire protection properties into the pure cotton fabric by layer-by-layer (LbL) technique. The optical properties and mass of the films were precisely controlled by the number of bilayers. In this case, CS and clay multilayer thin films were used to increase the thermal stability of the fabrics and improve the anti-flammable properties through the formation of a ceramic char layer and thermally stable carbonaceous structure at a high temperature. This study demonstrates the ability of the LbL technique to produce anti-flammable starch-clay nanocomposite thin films. Cone calorimetry showed the lower total heat release and heat release capacity of the LbL-coated fabric. The LbL-coated cotton samples exhibited a reduced afterglow time in vertical flame tests. An increased amount of residue indicates that the LbL technique is a simple method which can be used to produce eco-friendly flame retardant thin film coatings.