Asynchronous, online interactions are increasingly common, particularly in education, but relatively little is known about the influence of social identity in these environments. We test for the presence of race/place-of-origin and gender biases among students and instructors in asynchronous online post secondary classes by measuring responses to discussion comments posted in the discussion forums of 124 different massive open online courses (MOOCs). Each comment was randomly assigned a student name connoting a specific race/place of origin and gender. We find evidence that assumed identities influenced the likelihood of both instructor and peer responses. The comparative effects by identity indicate that instructor responses consistently privileged White males who were, on average, 94% more likely to receive a response than other students. We also find that White female students were particularly likely to receive a peer response. We discuss the implications of these findings for understanding social-identity dynamics in classrooms and the design of online learning environments.