"Grades or Growth?" is a research-based workshop class that inquires into the critical yet often overlooked realm of assessment within the domain of sustainability education or Education for Sustainable Development (ESD). While substantive progress has been made in developing innovative pedagogies and formulating sustainability-specific learning objectives, assessment practices have received limited attention so far. This workshop class addresses this gap. In the course, we will critically appraise available evidence and subjective experiences with examination and assessment procedures. Next, we will review alternatives to mainstream assessment and examination procedures and evaluate their compatability with the principles and aspirations of sustainability education. Finally, we will conduct orginal case studies of innovative practices. By scrutinizing innovative practices and methodologies, we will collectively gain insights into how assessment can better serve the transformative aims of sustainability education. We will also experiment with "walking the talk" by co-designing examination procedures in the course.