In this study, we aimed to examine how counseling service provided to college students, through a contextual clinical counseling model, affects the anxiety level of college students at a university in the east of Turkey. We followed a quasi-experimental with pretest-posttest and with control group design method. The experimental group comprised 205 and the control group comprised 75 college students. Seven supervisors with Ph.D. or MD degree in mental health professions provided weekly supervision to 120 counselors-in-training who provided individual counseling services to the participants. Each client in the experimental group received in average five sessions, each for 45-55 minutes. We have used an adapted version of Beck Anxiety Inventory for Turkey to examine the clients' anxiety levels. Throughout the counseling process, we have collaborated with the psychiatry department at the university when it was necessary. Additionally, in order to conduct the complex quasi-experimental study in a smooth process, we utilized the contextual clinical counseling model developed by the first author; as such models are utilized in some of the best counseling departments in the USA. The model facilitated to conduct the complex and dynamic research and providing the services with limited resources. That means optimized the resources through the model and got significant results. As a result, receiving counseling service seems significantly decreasing anxiety level for this sample. The current study meets some important gaps in mental health. We discussed the findings from an ecological systems theory perspective and suggested some implications in mental health.