Assessment bias is error that occurs consistently (i.e., not randomly), inflating or depressing the assessment scores of particular students. This white paper describes how Aperture Education thinks about assessment bias, why we believe it is important to address, and how we work to reduce it. We discuss how Aperture’s strength-based resources, including the Devereux Student Strengths Assessment (DESSA) and the DESSA-mini, were intentionally designed to minimize four types of assessment bias from influencing DESSA scores: rater bias, construct bias, item bias, and sample bias. We also describe how assessment bias can be further reduced through specific monitoring tools, training, and implementation practices that support their proper administration, interpretation, and communication. We conclude that although it is not possible to eliminate bias in all its forms, we have a duty to work to minimize it, and the impact it can have. The field of social and emotional learning assessment is relatively new, and we plan to continue discovering new ways of identifying, understanding, and mitigating assessment bias, so that we can accurately measure and continuously improve the well-being of children, youth, and adults.