Teachers need to make choices about how they distribute their time and support, and a school's vision may support teachers in making these choices. This study aimed to gain insight into how individual teachers--each with their own beliefs about fair classroom differentiation--handle differentiation dilemmas in the context of their school's vision. A case study was conducted at one primary school with a well-defined vision on classroom differentiation. In this school, quantitative and qualitative data were collected: 25 teachers filled in a questionnaire and four teachers sat for in-depth interviews. Teachers had varying beliefs about differentiation. Some beliefs were in line with the school's vision: these teachers preferred common learning goals and considered it fair to provide extra support to disadvantaged students. However, other teachers preferred individual learning goals and considered it fair to give every student an equal amount of support. Teachers whose vision was similar to that of the school perceived the differentiation dilemmas to be less problematic than teachers whose visions differed from the school's vision. A school vision on fair differentiation may help in making joint agreements, but it does not eliminate differentiation dilemmas. Teachers should discuss the differentiation dilemmas to achieve a shared vision on them.