Orientation and relaxation behavior in uniaxially stretched stereoregular polymethylmethacrylate (PMMA) was investigated. When compared at a reference temperature T = T-g + constant, isotactic PMMA orients more readily and relaxes slightly faster than the conventional or syndiotactic polymers. Orientation relaxation of the different PMMAs can be reduced to a unique master curve, whatever the tacticity, when the results are compared at same monomeric friction coefficient.