The main purpose of this study was to assess the effects of doodling on the learning performance of high school female students in Tehran. The design of this research was a pre-test-post-test with a control group. A group of 169 junior high school 12-13 year-old students was chosen for this study. After being taught a section of the Natural Science course, the students were asked to answer questions related to the lessons. After that, their grades were used as the pre-test scores. The post-test was carried out after the devised treatment. During ten sessions of the same course and teacher, the students were each given a blank sheet of paper and were asked for doodling if they felt like doing it. After each session, a couple of relevant written questions were asked to evaluate how well students had learned the lessons. The experiment and control group both consisted of 27 randomly selected students; participants in the experiment group were doodlers and those in the control group did not doodle. To evaluate the doodling effect a t-test analysis was performed. Comparison of the grades showed that the experiment group outperformed the control group significantly.