This study aims to investigate the effect of communication skills on EFL Iraqi pupils' achievement, specifically in their achievement in written skill, and its hypotheses are as the following: Firstly, there is no statistically significant difference between the mean scores of the experimental group who is taught by using communication skills, and the mean scores of the control group who is taught by traditional method in post achievement test. Secondly, there is no statistically significant difference between the mean scores of the experimental group who is taught by using communication skills in pre and post written achievement tests. To carry out the aims of this study, and validate its hypotheses, a sample of 60 pupils have been randomly chosen from the fifth-preparatory class in Al-Bassma Secondary School for Girls, during the academic year 2024-2025. The two groups are equally divided into, group (A) represents an experimental group that consists of 30 pupils who have been taught ف communication skills. While group (B) signifies a control group that also includes 30 pupils who have been taught by applying the conventional method. Pre-test and posttest are used to collect the data. This study reveals a significant difference in posttest scores between the experimental group who is taught through applying the communication skills and the control group who is taught through applying the conventional method. The results show that there is a statistically significant difference between the mean scores of experimental group who is taught by applying the communication skills in pre-post written achievement tests. This indicates that the communication skills are more effective than the conventional method. The study concludes some conclusions, recommendations, and suggestions for further studies.