Teacher professional learning is considered crucial for improving the quality of education. Teacher collaboration in professional learning communities can contribute to the effectiveness of professional development efforts. In the past decade, there has been a shift from within-school to between-school professional learning communities. However, results regarding their effectiveness have been inconsistent. In this study, we examine the effects of 23 networked professional learning communities in the Dutch context, using a mixed-methods approach. Results showed moderately positive effects on teachers' perceived satisfaction; the knowledge, skills, and attitude developed; and their application to practice. Considering the early stage of development of these professional learning communities, teachers' participation in networked professional learning communities seems promising for enhancing their professional learning.