With the complexity of students’ mental issues increasing rapidly during recent years, school guidance counselors are increasingly important and emphasized. However, we still have no research that explores the impact that having psychologists in schools has on school counselors. In this study, we explored the impact of having psychologists in schools on the level of job satisfaction of school counselors. Our research examined the relationships between role stress and job satisfaction of school counselors as well as the mediator role of interdisciplinary collaboration among school counselors and psychologists derived from the 2011 policy that brought psychologists into schools. In the analysis, we applied cluster-stratified sampling to divide Taiwan into four areas: Northern, Middle, Southern, and Eastern areas. We then conducted surveys according to the proportion of the number of schools in the four areas. The first class is county, and the second class is administration area. The participants were junior high school counselors who had worked with psychologists before, and we surveyed 485 school counselors in total. The data analysis included primary and advanced levels - in the primary level, we used descriptive statistics and Pearson’s correlation analysis. In the advanced level, we applied structural equation modeling to examine measurement model and structural model. After the model fit was confirmed, we conducted the mediation effects by using the bootstrapping method. This study showed the following results: (1) Among factors in role stress, the score of the score of role conflict was the highest impacting factor, followed by role overload (quality), with role overload (quantity) being the least impacting factor; among factors in interdisciplinary collaboration, the score of professional assistance was the highest impacting factor, followed by collaborative support, with school immersion being the least impacting factor; among factors in job satisfaction, the score of achievement development was the highest impacting factor, followed by professional growth, with interpersonal relationship being the least impacting factor. (2) On the measurement model, the results indicated that the research model fit our data, RMSEA = .064, SRMR = .04, GFI = .97, CFI = .98, IFI = .98, NFI = .96, PCFI = .65, and PNFI = .64. (3) The role stress of school counselors had a significantly negative effect on interdisciplinary collaboration. Also, interdisciplinary collaboration had a significantly positive effect on job satisfaction. (4) interdisciplinary collaboration plays a mediator role between role stress and job satisfaction. On one hand, role stress directly decreases job satisfaction. On the other hand, role stress first negatively associated with interdisciplinary collaboration, which in turn positively associated with job satisfaction. Finally, we suggested that schools should pay more attention to school counselors’ role stress and the potential negative impact of interdisciplinary collaboration on their job satisfaction. When school counselors are already under heavy role stress, working with psychologists could turn out to be a negative collaboration, instead of helping school counselors increase their job satisfaction. Additionally, we found out that psychologists tend to provide professional assistance but the level of immersion in schools scored the lowest in regards to collaboration. Thus, we believe that school immersion is important for psychologists who wish to work in the area of school guidance. Future research could add other independent measures into the model to examine the influence of interdisciplinary collaboration between school counselors and psychologists, such as work efficiency, guidance efficiency, or student guidance outcomes. In addition, researchers can also discuss the negative sides of interdisciplinary collaboration, including lack of collaboration awareness, role difference, or school system limitations. Finally, future research could benefit from applying the interdisciplinary collaboration scale on different professionals, particularly social workers, psychiatrists, homeroom teachers, or even administrative officers in order to understand their collaboration impact with school counselors.