Teachers' conceptions of assessment are important as they shape their usage of assessment practices. This study used a phenomenographic approach to examine the various purposes a sample of 26 New Zealand teachers ascribed to assessment. Seven purposes were discussed: compliance, external reporting, reporting to parents, extrinsically motivating students, organising group instruction, teacher use for individualising learning, and joint teacher-student use for individualising learning. This study showed that teachers held complex conceptions of assessment and described using different assessments for differing purposes. It highlighted how teachers must consider divergent stakeholder interests when selecting assessments for students, balancing the needs of the society, the school, and the pupil. The data emphasised the particularly strong tension between what teachers feel is best for students versus what is deemed necessary for school accountability. (Contains 1 table and 2 figures.)