In this lecture, a fractional order model for HIV/AIDS infection will be analyzed to study the effect of unaware infected individuals on the spread of HIV virus. The mathematical formulation of the model is based on the Caputo’s definition of fractional derivative. We simulate the model for different values of the fractional derivative order. Finally, numerical solutions are presented by using the Sinc approximation method to illustrate the dynamics between susceptible fractions and unaware infected fractions.