A synchronizer for a transmission including: a synchronizer hub; a synchronizer sleeve slidable thereon to engage with a clutch gear, which is provided with sleeve spline teeth having sleeve chamfers; and a synchro ring having a plurality of pairs of synchro ring spline teeth each having a synchro ring chamfer for receiving one of the sleeve chamfers. The synchro ring chamfer has a leading edge offset from the center of each synchro ring spline tooth, so that a distance between the leading edges becomes greater than a distance between the centers of the synchro ring spline teeth in each of the pairs of the synchro ring spline teeth. Moreover, the sleeve spline teeth are provided on the synchronizer sleeve only in angular positions between the synchro ring spline teeth of each of the pairs.