The objective of this study was to test the validity and efficacy of discrete-event simulation (DES) in modeling a specialty outpatient clinic, and to apply the model to predict how the clinic could improve their patient flow. Arena software was used to develop this DES model. Real-life model inputs included the time that patients spent in each clinic process, clinic room utilization rate, and physician room schedules. The DES was validated via a comparison between the model’s outputs and raw clinic data, and further validated by clinic leadership. Once validated, the DES was modified to represent different scenarios, such as changes in clinic scheduling and resource usage. Analysis of the models revealed that adding two volunteers to escort patients in the morning and afternoon would decrease the queue time to see a physician by 33.9% and 65.2% respectively. The model results also suggested that there is currently not enough congestion in the clinic for changing the current dedicated room assignment to un-assigned room scheduling to make a significant difference in any of the clinic queue sizes. The results of the analysis and validation support the usability of DES in modelling and analysis of specialty outpatient clinics and providing decision support.