This study aimed to investigate the effect of using systemic approach in organic chemistry achievement and retention among grade eleven female students. The study sample consisted of (65) female students from 11th grade of post basic education in Muscat's schools during the academic year 2011/2012. The sample was divided into two groups: an experimental group (N=33), which was taught using systemic approach and a control group (N=32), which was taught by the conventional method. To achieve the study aims, a guide for teacher who taught the experimental group was developed and 25-item achievement test was administered. The achievement test was verified by a judge of experts and its reliability coefficient Alfa Cornbach was (0.89). The test was administered twice, first after finishing from teaching the unit and then after three weeks. The findings of the study reveals that there were significant statistical differences in both organic chemistry achievement and retention at (a = 0.05) between experimental and control group in favor of experimental group. Consequently, the researcher proposed several recommendations, such as: conducting workshops and training courses for supervisors and science teachers to use systemic approach in science teaching and doing further researches in systemic approach in science teaching.