This paper analyzes teachers' motivations and expectations when engaging in action research and relates these to the process outcomes and to the broader evidence movement in education. The theoretical framework builds on research on motivations for teaching and engaging in action research. The empirical data consisted of 50 written teacher reflections completed on two occasions within the action research and teachers' oral presentations using PowerPoint slides. The outcomes regarding individual and collegial professional learning corresponded well to the teachers' expectations. However, the relationships with their principal, and also with the researcher, developed more than had been expected. Also, the teachers saw evidence of student/child learning in line with the intentions, but the fact that social and emotional learning was, ultimately, more visible, was unexpected. This study shows that action research, based on an evidence-informed perspective, plays an important role when teachers are building a research-based education, in a context where evidence-based teaching is promoted. Implications of this study include: the importance of establishing fair conditions for teachers' voluntary engagement in action research; highlighting intentions in the beginning, and throughout the process, which increases the probability of achieving the expected outcomes; and promoting teacher-driven processes.