This article describes a cycle of teacher collaborative inquiry called the Student Experience Improvement Cycle (SEIC). The SEIC is a novel form of assessment: it focuses on supporting teachers in using evidence of the quality of student experience formatively to make the classroom more equitable. The SEIC begins by setting a goal for improvement in one of three aspects of student experience: coherence, relevance, and contribution. Then, teachers review, adapt, and test research-based strategies for improving the quality of student experience overall and for students from systemically marginalized groups and communities. The article presents examples of improvement goals teachers set and the strategies they tried as part of one inquiry cycle. It also provides examples of survey items used to elicit student experience.