Classroom assessment has always been an indispensible and integral part of any curriculum. In particular, assessment plays the role of reporting students' learning summatively (assessment of learning), providing diagnostic and formative information for teachers to inform their instruction (assessment for learning); more recently, Earl (2013) proposed the notion of assessment as learning, which puts students at the center of assessment. Students in this assessment paradigm act as critical connecters between assessment and learning through self-reflection and self-regulation. The first section of this article reconceptualizes summative and formative assessments into three assessment paradigms: assessment of, for, and as learning through incorporating Serafini's assessment models and Habermas's three human interests. In so doing, our understanding of the three paradigms is consolidated and enriched to encompass not only the pedagogical implications but also their philosophical and epistemological underpinnings. The second section of the article focuses on one particular kind of assessment method commonly used in language classrooms, which is written feedback. I summarize and categorize recent written feedback research with reference to the three assessment paradigms and suggest directions for future research.