In 2015, for the first time in its history, PISA (the Programme for International Student Assessment) asked teachers to describe the various aspects of their working environment and teaching practices. This paper examines how teacher, student, and school characteristics are related to science teachers' satisfaction in 19 PISA-participating countries and economies. The findings show that the most satisfied science teachers tend to be those who are initially motivated to become teachers. The results also highlight the positive relationship between science teachers' satisfaction and teacher collaboration, good disciplinary climate in science classes, availability of school resources, and the opportunity to participate in professional-development activities.