Thematic analysis (TA) is widely used in qualitative psychology. In using TA, researchers must choose between a diverse range of approaches that can differ considerably in their underlying (but often implicit) conceptualizations of qualitative research, meaningful knowledge production, and key constructs such as themes, as well as analytic procedures. This diversity within the method of TA is typically poorly understood and rarely acknowledged, resulting in the frequent publication of research lacking in design coherence. Furthermore, because TA offers researchers something closer to a method (a transtheoretical tool or technique) rather than a methodology (a theoretically informed framework for research), one with considerable theoretical and design flexibility, researchers need to engage in careful conceptual and design thinking to produce TA research with methodological integrity. In this article, we support researchers in their conceptual and design thinking for TA, and particularly for the reflexive approach we have developed, by guiding them through the conceptual underpinnings of different approaches to TA, and key design considerations. We outline our typology of three main "schools" of TA-coding reliability, codebook, and reflexive-and consider how these differ in their conceptual underpinnings, with a particular focus on the distinct characteristics of our reflexive approach. We discuss key areas of design-research questions, data collection, participant/data item selection strategy and criteria, ethics, and quality standards and practices-and end with guidance on reporting standards for reflexive TA.