The effects of adaptation of New Taxonomy on 11th grade Language and Oral Expression unit on students achievement is examined in this study. There are one experimental and one control groups. Each group has been given a pre and post test 'achievement test'. In both groups there have been significant differences on the part of the post test scores among the pre and post test scores. As examined by ANCOVA; between the post test scores, those are corrected according to pre test scores; there has been significant difference on the part of experimental group. Some recommendations were made in the light of these findings.