In a case study in five Dutch primary schools teachers reported that they are reluctant to speak their minds, propose new ideas and give feedback to colleagues (Hulsbos et al., 2016). The study indicated that there is a lack of professional relatedness in these schools, a type of relationship between colleagues that is based on trust, mutual respect and a shared vision. The authors argue that professional relatedness supports teacher professional development (TPD) through supporting social learning. To further explore the concept of professional relatedness in Dutch schools and its relationship to TPD a PhD project has been initiated. The aim of the PhD project is, amongst others, to develop an instrument and intervention specifically designed for Dutch schools to study and enhance professional relatedness and TPD. The main questions for this roundtable session focus on the development of the instrument and intervention.