The article analyses the trust relationship between principals and teachers in primary schools in the specific Chilean educational context. The analysis is based on the concept of school trust, emphasizing Bryk and Tschannen-Moran's classic works. A mixed sequential quantitative-qualitative research methodology is used, including both a survey and a qualitative case study carried out in nine schools. The main results, include: principals and teachers take a different approach when forging trust they have in one another. While principals confer this trust, teachers earn it. Likewise, principals mainly set the tone, intensity and scope of the trust relationship; principals are more critical of teachers, mainly questioning certain aspects of their professional skills. Conversely, teachers normally base trust on more personal matters; individual traits of both principals and teachers have little impact on their relational trust, the exception being the number of years teachers have been on the job. While for teachers there are hardly any differences (and this changes only when it comes to the prevailing principal's leadership), among principals, differences emerge from schools' size, socio-economic level and public or private status; and a final discussion propounds the importance of the educational context when analysing trust relationships and positional power in schools.