The present study aimed to study the impact of Virtual Writing Tutor (VWT) software on the academic writing skills of Year 1 Omani EFL students in the College of Applied Science, (CAS)-Sohar and their attitudes towards using VWT software to improve their academic writing skills. Additionally, it aimed to investigate the required design principles for the effective utilization of the VWT software in Omani EFL education from the perspectives of EFL Subject Matter Experts (SMEs) and instructional designers (IDs). A quasi-experimental design was adopted to achieve the current research objectives. The sample consisted of 35 students in the control group and 35 in the experimental group (Total N= 70) who were enrolled in the English for Academic Purposes (ENAP1002) course at CAS-Sohar. The sample also included 6 SMEs and 6 IDs. The data collection instruments included pre-test and post-test for the control and experimental groups, attitude scale for the experimental group, and a design principles checklist and interview for the IDs and SMEs. The findings of the study showed a positive large effect size (Cohen's d = 0.88) of VWT on writing skills. In addition, Year 1 students in the experimental group enjoyed using the VWT software and found it beneficial and helpful in checking the accuracy of their essays including spelling, punctuation, grammar and vocabulary. Finally, both IDs and SMEs agreed that content, technical soundness and user-flexibility were the most effective design principles applied to the VWT software. More interestingly, they both considered assessment and feedback as the least effective design principle applied to its utilization of VWT software. In light of the research findings, implications and recommendations for future research were outlined.