The materials with the chemical composition of higher levels of carbon, hydrogen, and oxygen are often more combustible than those with the lower levels of these elements. The flammability qualities of SR biocomposites are greatly influenced by the loading of nanofillers and the composition of the fillers. The flammability properties of the materials and the measurement of flammability by various testing methods are discussed in detail. The flammability measurement techniques like oxygen index test, smoke density test, and test for fire propagation are highlighted in this chapter. The ignition temperature, smoke production rate, and release of any flammable gas or vapor during combustion must be taken into account while assessing the flammability of the materials. The flammability properties and the flammability measurement using various testing methods are discussed in detail. The chapter also outlines the flammability measurement techniques like the UL94 test, oxygen index test, smoke density test and fire propagation test with the aim of providing insightful information on a material’s flammability and fire behavior. The reinforcing effect of natural fillers like montmorillonite (MMT), sepiolite, and silica on the flame retardancy of silicone rubber biocomposites is also summarized.