Diversity has an important, multifaceted role in the success of education. I have used a corpus analysis of the first ten years of Physical Review Physics Education Research to investigate the diversity, broadly defined, of physics education research. The results show that the physics education research community has extensively investigated the diversity of physics students, especially with respect to gender. However, some less visible but still numerous groups of students are little studied. On the whole, the contents of Physical Review Physics Education Research reveals a robust research community in physics education, but there is room for growth with respect to working with different kinds of students and the interactions between student attributes and teaching methods.