Background/Context: Despite noted difficulties with defining and assessing teacher dispositions, U.S. state education departments and national accreditation agencies have included dispositions in mandates and standards both for determining teacher quality and for assessing the quality of the teacher preparation programs that certify them. Thus, there remains a significant impetus to specify dispositions to assess, identify what "good" dispositions look like in practice, and determine the best way to measure them. Purpose: The purpose of this paper is twofold. First, we aim to problematize the construct of "teacher dispositions" through a critical synthesis of literature and a discussion of a rhizomatic perspective to generate a (re)conceptualization that is more closely aligned with the immensely complex nature of teaching and learning. Second, we draw on samples of university-generated teacher disposition assessment tools to provide concrete examples that "put to work" this complex perspective on dispositions. Research Design: To apply ideas introduced in our rhizomatic framework focused on multiple, dynamic assemblages, we conducted a qualitative textual analysis of a sample of 16 widely available assessment tools used by university-based teacher preparation programs to measure teachers' professional dispositions. Findings and Conclusions: Overall, the vast majority of disposition criteria included in the tools reviewed were temporal and relational, seeking to assess the interactions of the teacher candidate amidst a variety of potential circumstances as well as material and discursive factors. This reveals a paradox, however, since, despite their more contextual phrasing, these criteria ultimately seek to assess an individual and are high-stakes only for that teacher. Yet, we suggest that the results of this review may be an indication that the field is moving toward a more multifaceted vision of teaching that can better take into account the dynamic, situated, and relational nature of teaching activity. We also suggest the language accounting for some of the complexity of teaching in the disposition assessment tools we reviewed may be an entry point into a more dynamic, vital materialist vision of the profession.