In the literature, there are several numerical integration formulas and many researchers have been investigating the error bounds of these formulas forseveral function classes such as convex functions, bounded functions, Lipschitzian functions, functions of bounded variation, etc. In thisresearch article, we obtain some Milne type inequalities to the case of Riemann-Liouville fractional integrals by means of some important functionclasses. This is the first paper focusing on fractional Milne type inequalities.