In this chapter, a novel technique for measurement of refractive index of different materials using moiré pattern is proposed. This method uses incoherent moiré pattern that forms due to mechanical superposition of two periodic structures such as gratings or repetitive lines. The resultant low-frequency moiré pattern, consisting of alternating bright and dark lines called ‘fringes’, are dependent on the refractive index of the intercepted medium between the periodic structures. It has been noticed that these fringes shift due to changes in refractive indices. Consequently, by measuring this shift, refractive indices of liquids, kept suitably within a designed optical set-up, can be calculated in the proposed technique. The technique is highly sensitive, so these measurements of refractive indices of different liquids can be used for measuring adulteration or other characterizations. Here only transparent liquid samples have been considered for this measurement and an accuracy of 10−2 after decimal in Refractive Index (R.I.) has been achieved. © 2020, Springer Nature Singapore Pte Ltd.