The R-equivalence is an equivalence relation on points of algebraic varieties that was introduced by Yuri Manin and
proved to be very fruitful in the study of groups of points of algebraic groups. We propose a generalization of the notion of R-equivalence to schemes over arbitrary commutative rings that leads to natural extensions of several well-known results on R-equivalence for algebraic tori and simple algebraic groups to the case of reductive group schemes.