Effective and collaborative supervision of language teachers involves understanding teacher and learner characteristics and needs, approaching supervision from a developmental rather than an evaluative perspective, and engaging in reflective communication. Teacher observation is an important component of supervision, and there are various ways that teacher supervisors can approach this task. There are also many positive reasons for conducting teacher observations using a collaborative approach. Observations can give administrators an understanding of how teachers are carrying out instruction; the ways that curriculum, materials, and special projects are implemented within and across levels; difficulties that students may be having; advantages and challenges of using technology; and promising instructional practices that can be shared with other teachers. This brief addresses three types of observations: formal, walk-through, and alternative. Each type is described, and examples are provided for implementation within a collaborative approach to adult ESL teacher supervision. (Contains 1 note.) [For companion to this brief, "Supporting and Supervising Teachers Working With Adults Learning English," see ED505393.]