Using data collected from 120 students enrolled in nine sections of an undergraduate technical communication course, this study found a number of statistically significant associations between students' learning styles, as defined by the Index of Learning Styles, and nine measures evaluating both academic performance and student preference. The study also measured student performance in collaborative and self-directed versions of the course, as well as full and summer sessions. Reflective learners were found to be the most successful online learners, excelling in collaborative, as well as self-directed versions of the course. Sequential learners also outperformed global learners. Learning styles were not a significant factor in summer-session courses. (Contains 1 figure and 1 table.)