In this book, we are primarily concerned with the periodicity of non-linear difference equations which are rational, max-type, special-type and the system of rational difference equations. This book consists of six chapters. In Chapter 1, we give the necessary preliminary definitions and some examples of linear and non-linear difference equations. In Chapter 2, we present some examples of the periodicity of some rational difference equations. In Chapter 3, we exhibit some examples of the periodicity of some max-type non-linear difference equations. In Chapter 4, we present some examples of the periodicity of some special-type difference equations. In Chapter 5, we investigate the study of some special max-type difference equations with eventually periodic solutions. In Chapter 6, we present some examples of the periodicity of the system of rational difference equations. It is hoped that this work can be useful for students and researcher that are interested in difference equations