This paper begins with an overview of several instruments for assessing the school environment, focusing on Moos's Work Environment Scale (WES). Although the WES was designed for use in any work milieu, its 10 dimensions of work environment (involvement, peer cohesion, staff support, autonomy, task orientation, work pressure, clarity, control, innovation, and physical comfort) seem well suited to describing salient features of the teacher's school environment. The second part of the paper considers the validity of the WES when used for the first time specifically with school teachers. For example, administration of a slightly reworded version to 114 science teachers in 35 high schools revealed KR-20 reliability coefficients ranging from 0.60 to 0.85. The WES has now been cross-validated with larger samples of elementary and high school teachers responding to both an actual form (N=599) and a preferred form (N=543). Data analyses attest to the internal consistency, reliability and discriminant validity of both WES forms. The third part of the paper considers applications of the WES in science education and, in particular, presents profiles depicting interesting differences in the environments of elementary schools and high schools. For example, high school teachers (compared to elementary teachers) characterized their school environments as involving less work pressure. (Author/JN)