Background: Many education systems internationally expect schools to participate in continuous instructional improvement programmes. One tool used within these processes is the structured, rubric-based classroom observation, focused on the evaluation of teaching. Such observations are a common feature of formative evaluation systems, teacher coaching programmes, within-school teacher collaborative structures, and other local, regional or national frameworks. However, a question arises as to how rubric-based observations may better support teacher learning and development. Purpose and sources: Drawing on existing theoretical arguments and empirical work, this paper seeks to contribute to discussion about rubric-based classroom observation and its relationship with teacher learning and instructional improvement. Main arguments: Observation rubrics can be regarded as summaries of a community's understanding of good instruction. When generated in a way that makes this understanding accessible to teachers in the context of their own practice, they have the potential to place the rubric's, and teachers', understandings of good teaching 'in conversation' with each other. This could provide valuable opportunities for teachers to refine and expand their understandings of good instruction. Embedding rubric-based observations in school structures can, thus, facilitate continuous improvement efforts by better supporting teacher self-reflection, feedback, and collaboration. However, many uses of observation within school contexts tend to prioritise the rubric's, rather than teachers', understanding of good teaching. This risks turning observations from tools of learning into tools of judgement, disrupting the pathway through which they might support teacher learning and instructional improvement. Conclusion: Our discussion draws attention to the potential benefits yielded and the challenges that may occur in using rubric-based observations to support teacher learning. It highlights factors that need consideration in efforts to leverage rubric-based observations to better promote continuous teacher learning, ultimately positively influencing student learning.