This study is an examination of an Internet-based tutorial that teaches the concept of positive reinforcement. An experimental group of 50 students studied an online tutorial about positive reinforcement, and a control group of 50 students studied an online tutorial in biological psychology. Students in both groups took an 8-item pretest and posttest over positive reinforcement. An analysis of the students' change scores indicated that the students benefitted from the positive reinforcement tutorial. Students rated the positive reinforcement tutorial highly on several dimensions. I discuss the desirability of greater sharing of Internet-based educational resources as a means of providing students with a wide variety of low-cost online instructional software.