Purpose: The purpose of this study was to explore preservice teachers' experiences of cognitive disequilibrium (CD) theory during a service-learning project in a study abroad experience. Method: A case study with 8 participants was used. Data sources consisted of: Formal interviews, videos of planning, videos of teaching, videos of reflection sessions, and informal interviews. Data were analyzed utilizing open and axial coding (Corbin & Strauss, 2008). Trustworthiness strategies included: prolonged engagement, multiple data source triangulation, and member checks. Results: Results indicated four themes: "We made it our own thing", "Summer camp for teachers", "Struggle and disequilibrium", and "By the end it was a transformation". Discussion/Conclusions: CD was ultimately positive for these students. The positive resolution of CD catalyzed a transformative effect on their perceptions of their teaching. This was supported by positive peer interaction.