This paper discusses what makes a high-quality online teacher, examining: what it takes to be a high-quality teacher (knowing one's subject and how to teach it); what is unique about online teaching (online teachers rarely see their students, need strategies to ensure that each online student participates actively, and provide courses online so are able to work any time and any place); and how the quality of online teaching is assessed. A checklist identifies essential qualities of online teaching to help states and schools select, train, and evaluate online teachers. It discusses: state qualifications (the extent to which the teacher meets the state standards for professional teaching); curriculum, instruction, and student assessment (the extent to which the teacher meets the criteria in such areas as promoting student participation and interaction and using online resources effectively to deliver instruction); management (the extent to which the teacher meets the criteria in such areas as providing students with timely feedback and ensuring that students' work and data are secure); and evaluation (the extent to which the teacher meets the criteria in such areas as understanding that student success is an important measure of course success and ensuring that students participate actively in the course). (SM)