Philosophy is a reflective activity. So perhaps it is unsurprising that many philosophers have claimed that reflection plays an important role in shaping and even improving our philosophical thinking. This hypothesis seems plausible given that training in philosophy has correlated with better performance on tests of reflection and reflective reasoning has correlated with demonstrably better judgments in a variety of domains. This article reviews the hypothesized roles of reflection in philosophical thinking as well as the empirical evidence for these roles. This reveals that although there are fairly reliable links between reflection and philosophical judgment among both laypeople and philosophers, the role of reflection in philosophical thinking may nonetheless depend in part on other factors, some of which have yet to be determined. So progress in research on reflection in philosophy may require further innovation in experimental methods and psychometric validation of philosophical measures.