Motivation is considered an element essential for success in the online classroom, and, in order to inform online teachers' pedagogical practices, this quantitative, descriptive study explored teachers' perceptions of high school students' motivation in the online learning environment. Identified by convenience sampling, 22 online high school teachers from a national K-12 curriculum provider located in the northeastern United States responded to a modified Perceptions of Student Motivation questionnaire (PSM), four demographic questions, and one open-ended question. Results indicated that teachers did not decisively perceive their students as motivated or unmotivated, and, overall, believed that effort was more influential than engagement or general interest as a motivator in the online classroom. Results also indicated that teachers believed current relevance/value was the most significant cause of lack of student motivation in the online high school classroom. According to the responses from the open-ended question, teachers postulated that multiple factors influenced students' motivation, factors which were beyond the teachers' control, supporting the literature that motivation is complex and multi-faceted. These findings suggest that teachers continually monitor their perceptions of students' motivation, their perceived reasons for lack of students' motivation, and the accuracy of such perceptions. The results also support the deliberate consideration of motivation in all dimensions of online learning. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]