This quasi-experimental study explores the impact of Edmodo application on students' achievement in language skills and retention in EFL context. Fifty three eleventh grade students participated in this study. A quasi-experimental design was used to measure the effect of Edmodo application. The study dealt with hypotheses to compare between the experimental and control groups, independent t-test was used to determine if there are significant differences in students' achievement in post-test and retention between experimental and control groups. Tests data were analyzed using several statistics. Results suggested significant differences in students' language skills acquisition and retention in favor of experimental group. There were no differences in students' speaking, listening, and structures for the control group, whereas there are significant differences in vocabulary, reading, writing and total score. Independent t-test results revealed that there are significant differences in students' achievement in post-test and retention between experimental and control groups in favor of the experimental.