The purpose of this investigation was to examine the relationships among measures of student engagement, instructor engagement, student performance, and properties of the online classroom. The authors assessed behavioral, cognitive, and emotional engagement of students and instructors in asynchronous discussion forums and collected measures of student performance (e.g., class completion and discussion forums' grades) as well as properties of the online classroom (e.g., class size and depth of discussion prompts). Quantitative analyses on conduct exhibited by instructors and students in discussion forums from 303 online classrooms in a variety of disciplines revealed a positive association of students' cognitive engagement and instructors' behavioral engagement with the depth of the discussion prompts. Both cognitive and behavioral measures of students' engagement decreased with increased class size. For instructors, as class size increased, behavioral engagement decreased, and cognitive engagement increased. Grades improved with students' emotional engagement but declined with instructors' cognitive engagement. These idiosyncratic patterns of relationships suggest the need for further inquiry into the unique aspects of instruction in the asynchronous online classroom.