This report is the third in a series examining the magnitude of the teacher shortage and the working conditions and other factors that contribute to the shortage. The series finds that the teacher shortage is real, large and growing. When indicators of teacher quality (certification, relevant training, experience, etc.) are taken into account, the shortage is even more acute than currently estimated, with high-poverty schools suffering the most from the shortage of credentialed teachers. This third report focuses on a likely factor behind why teachers are leaving the profession and fewer people are becoming teachers: teacher pay. Specifically it looks at how teacher compensation compares with compensation in nonteaching occupations. It also delves into an aspect that has received increasing attention recently, which is whether teachers work multiple jobs, and what share of teachers supplement their earnings by moonlighting. Teachers who end up quitting their jobs received, on average, lower salaries, they participated less in the kinds of paid extracurricular activities that complement their professional development (activities like coaching students or mentoring teachers), and they participated more in working options outside the school system than did teachers who stayed at their schools. In high-poverty schools, teachers face compounded challenges. Relative to teachers in low-poverty schools, teachers in high-poverty schools are paid less, receive a smaller amount from moonlighting, and the moonlighting that they do is less likely to involve paid extracurricular or additional activities for the school system that generate extra pay but also help them grow professionally as teachers. The report discusses the likely influence of the large and rapidly growing "teacher pay gap"--how much less teachers earn than their comparably educated peers in other professions--on the weakening attractiveness of public education as a profession, and on the rising rate of teacher attrition.