This study intended to investigate the effect of using authentic texts on Iranian EFL learners' incidental vocabulary learning. To this end, a population of 52 Iranian female EFL learners aged 15 to 17 was selected. They were two intact classes; experimental group (25 students) and control group (27 students). Both groups received a pretest at the first session. Regarding the treatment, the authentic reading texts selected from World News for students of English, Level1 was taught to the experimental group while the texts selected from book 1 was taught to the control group. After a month post-test were run among all of the participants in both control and experimental groups to find out the possible effects of the treatment on the participants' vocabulary improvement. The analysis of data paired samples t-test and independent samples t-test showed that there was a significant difference between the post-tests of experimental and control groups. The experimental group outperformed the control group on the post-test.