The present study aimed at investigating the effect of using wikis on developing business writing skills and reducing writing anxiety of Business Administration students at Prince Sattam bin Abdul Aziz University, KSA. Sixty students, who were randomly chosen and divided into two equivalent groups: control and experimental, participated in the study. Two main tools were devised to collect data: Test of Business Writing Skills (TBWS) and Writing Anxiety Inventory (WAI). The experiment was conducted during the second semester of the academic year 2015-2016. A t-test was utilized to calculate the differences between the mean scores of the two groups in pre- and post-intervention. The findings of the study showed statistically significant differences between the mean scores of the experimental group and the control group on the post-TBWS in favor of the experimental group. In addition, the writing anxiety level of the experimental group, after the intervention, was significantly less than the control group. These findings revealed the positive effects of wikis on developing business writing skills and reducing writing anxiety of EFL learners. It is recommended that sufficient training should be provided to instructors on how to integrate wikis in business writing instruction. Pedagogical implications and suggestions for further research are presented.